The long-standing collaboration with Chang-Beom Eom at the University of Wisconsin-Madison, who provided the LAO/STO samples, is gratefully acknowledged. Video editing assistance from Christopher Solis is greatly appreciated. This work is supported by NSF (DMR-1104191, DMR-1124131), ARO (W911NF-08-1-0317), and AFOSR (FA9550-10-1-0524, FA9550-12-1-0268, FA9550-12-1-0057).

1. Ottenere LAO / STO Eterostrutture <ol><li> Ottenere un eterostruttura ossido costituito da 3.4 celle elementari di LAO coltivati ​​da deposizione laser pulsata su TiO substrati STO 2-terminati. Dettagli di crescita campione sono descritti in rif. 22. </li></ol> 2. Fotolitografica Trattamento dei campioni Creare contatti elettrici per l&#39;interfaccia LAO / STO, con cuscinetti di legame per tele di cablaggio ad un chip carrier. Le singole fasi di lavorazione sono descritte in dettaglio di seguito. <ol><li> Spin fotosensibile <ol><li> Spin photoresist sui campioni a 600 rpm per 5 secondi, poi a 4000 rpm per 30 sec. Lo strato fotosensibile sarà spessore di circa 2 micron. Cuocere i campioni a 95 ° C per 1 min. </li></ol></li><li> Esporre photoresist utilizzando un allineatore maschera con luce 320 nm per 100 sec con una dose di 5 mW / cm 2. </li><li> Sviluppare il photoresist in sviluppatore fotosensibile for 1 min. </li><li> Ion fresatura <ol><li> Utilizzare un mulino ioni Ar + per rimuovere i 15 nm di materiale (LAO e STO) nelle zone non coperte da photoresist. Porre i campioni con un angolo di 22,5 ° rispetto alla direzione perpendicolare al fascio di ioni Ar + in entrata. Se la velocità di attacco Ar + non è tarato, eseguire una corsa di taratura per garantire la corretta quantità di materiale viene rimosso. Determinare la profondità di incisione con AFM o profilmetry equivalente. </li></ol></li><li> DC sputtering di Ti e Au <ol><li> Cassetta 4 nm Ti, poi 25 nm Au sui campioni in modo che l&#39;Au fa contatto elettrico con lo strato STO esposto. La pressione sputtering è nell&#39;intervallo 2-6 x 10 -7 Torr, e lo sputtering avviene con il campione a temperatura ambiente. Pre-polverizzazione catodica Ti per 10 min con otturatore chiuso a 100 W, poi otturatore aperto e polverizzazione catodica per 20 secondi a 100 W. Al termine, immediatamente pre-sputter Au per 1 min a 50 W poi polverizzare Au per 30 sec per i campioni a 50 W. CaliBrate il tempo per produrre gli spessori Ti e Au desiderati. </li></ol></li><li> Lift-off <ol><li> Utilizzare lavaggio ultrasonico Acetone / IPA per rimuovere photoresist dalla superficie dei campioni. </li></ol></li><li> Secondo strato <ol><li> Un secondo processo litografico, escluso il punto 4 (ie., Escludendo la fresatura di ioni), viene utilizzato per creare i collegamenti dei cavi d&#39;oro ai singoli pad legame. I due modelli devono essere ben allineate per garantire che essi non producono cortocircuiti. </li></ol></li><li> Pulizia al plasma. <ol><li> Un IPC Barrel Etcher viene utilizzato per rimuovere il photoresist residuo nella trincea pattern. Lo strumento utilizzato al 100 W e 1 Torr argon per 1 min </li></ol></li></ol> 3. Wire James Bond un campione prepararsi per la scrittura <ol><li> Montare il campione LAO / STO in un chip carrier (Figura 2A) con 28 pin disponibili. </li><li> Struttura legame Wire </li></ol> NOTA: Utilizzare un bonder filo per fare c elettricaollegamenti tra i rilievi di legame sul campione e il chip carrier. Attaccare 1 mil (25 micron) fili d&#39;oro tra i contatti elettrici e il chip carrier. Scrivi nanostrutture 4. Scrivere Nanostrutture <ol><li> Creare uno schizzo informale della nanostruttura conduttrice (Figura 3A). </li><li> Aprire le Scalable Vector Graphics (SVG), montaggio (Figura 3B). <ol><li> Utilizzare un modello o definire le dimensioni della finestra in base a quella dell&#39;immagine AFM. </li><li> Caricare l&#39;immagine AFM del campione nell&#39;editor SVG. </li><li> Creare elementi di nanostrutture sovrapposte l&#39;immagine AFM su. </li></ol></li><li> Caricare il file SVG nel programma nanolitografia. </li><li> Eseguire il software di litografia per creare una nanostruttura conduttrice. <ol><li> Suggerimento Utilizzare V = +10 V per creare nanostrutture, e mancia V = -10 V per cancellare nanostrutture. </li><li> Spostare la punta c-AFM ad una velocità compresa tra 200 nm / sec a 2 micron / sec. </li></ol></li></ol> 5. Raffreddare dispositivo e prendere le misure <ol><li> Spegnere tutte le luci bianche e utilizzare filtri rosso / sorgenti luminose. </li><li> Estrarre il campione dal sistema AFM. </li><li> Caricare il campione in frigorifero diluizione (A). </li><li> Misurare la resistenza in funzione della temperatura (B) come il campione viene raffreddato. </li><li> Misurare le proprietà di trasporto a basse temperature (C). </li></ol>

<ol>
	<li>Sulpizio, J. A., Ilani, S., Irvin, P., Levy, J. i. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Annual Review of Materials Research, in press. , (2014).</li><li>Mannhart, J., Blank, D. H. A., Hwang, H. Y., Millis, A. J., Triscone, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-Dimensional+Electron+Gases+at+Oxide+Interfaces.">Two-Dimensional Electron Gases at Oxide Interfaces.</a> Mrs Bulletin. 33, 1027-1034 (2008).</li><li>Zubko, P., Gariglio, S., Gabay, M., Ghosez, P., Triscone, J. -. M., Langer, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Annual+Review+of+Condensed+Matter+Physics.">Annual Review of Condensed Matter Physics.</a> Interface Physics in Complex Oxide Heterostructures. , 141-165 (2011).</li><li>Bogorin, D. F., Irvin, P., Cen, C., Levy, J. i., Tsymbal, E. Y., Dagotto, E. R. A., Chang-Beom, E., Ramesh, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Multifunctional Oxide Heterostructures. 13, (2012).</li><li>Granozio, F. M., Koster, G., Rijnders, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+Oxide+Interfaces.">Functional Oxide Interfaces.</a> MRS Bulletin. 38, 1017-1023 (2013).</li><li>Ohtomo, A., Hwang, H. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-mobility+electron+gas+at+the+LaAlO3/SrTiO3+heterointerface.">A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface.</a> Nature. 427, 423-426 (2004).</li><li>Reyren, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superconducting+interfaces+between+insulating+oxides.">Superconducting interfaces between insulating oxides.</a> Science. 317, 1196-1199 (2007).</li><li>Bark, C. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Switchable+Induced+Polarization+in+LaAlO3/SrTiO3+Heterostructures.">Switchable Induced Polarization in LaAlO3/SrTiO3 Heterostructures.</a> Nano Letters. 12, 1765-1771 (2012).</li><li>Brinkman, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+effects+at+the+interface+between+non-magnetic+oxides.">Magnetic effects at the interface between non-magnetic oxides.</a> Nature Materials. 6, 493-496 (2007).</li><li>Thiel, S., Hammerl, G., Schmehl, A., Schneider, C. W., Mannhart, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tunable+quasi-two-dimensional+electron+gases+in+oxide+heterostructures.">Tunable quasi-two-dimensional electron gases in oxide heterostructures.</a> Science. 313, 1942-1945 (2006).</li><li>Cen, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoscale+control+of+an+interfacial+metal-insulator+transition+at+room+temperature.">Nanoscale control of an interfacial metal-insulator transition at room temperature.</a> Nature Materials. 7, 298-302 (2008).</li><li>Singh-Bhalla, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Built-in+and+induced+polarization+across+LaAlO3/SrTiO3+heterojunctions.">Built-in and induced polarization across LaAlO3/SrTiO3 heterojunctions.</a> Nature Physics. 7, 80-86 (2011).</li><li>Li, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Very+Large+Capacitance+Enhancement+in+a+Two-Dimensional+Electron+System.">Very Large Capacitance Enhancement in a Two-Dimensional Electron System.</a> Science. 332, 825-828 (2011).</li><li>Xie, Y., Hikita, Y., Bell, C., Hwang, H. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+electronic+conduction+at+an+oxide+heterointerface+using+surface+polar+adsorbates.">Control of electronic conduction at an oxide heterointerface using surface polar adsorbates.</a> Nature Communications. 2, 494 (2011).</li><li>Bark, C. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tailoring+a+two-dimensional+electron+gas+at+the+LaAlO3/SrTiO3+(001)+interface+by+epitaxial+strain.">Tailoring a two-dimensional electron gas at the LaAlO3/SrTiO3 (001) interface by epitaxial strain.</a> PNAS. 108, 4720-4724 (2011).</li><li>Tra, V. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Adv Mater. 25, 3357-3364 (2013).</li><li>Cronenwett, S. M., Oosterkamp, T. H., Kouwenhoven, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Tunable+Kondo+Effect+in+Quantum+Dots.">A Tunable Kondo Effect in Quantum Dots.</a> Science. 281, 540-544 (1998).</li><li>Cen, C., Thiel, S., Mannhart, J., Levy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxide+Nanoelectronics+on+Demand.">Oxide Nanoelectronics on Demand.</a> Science. 323, 1026-1030 (2009).</li><li>Kalinin, S. V., Gruverman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Scanning probe microscopy: electrical and electromechanical phenomena at the nanoscale. 1, (2007).</li><li>Piner, R. D., Zhu, J., Xu, F., Hong, S. H., Mirkin, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term='Dip-pen'+nanolithography.">'Dip-pen' nanolithography.</a> Science. 283, 661-663 (1999).</li><li>Ahn, C. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonvolatile+Electronic+Writing+of+Epitaxial+Pb(Zr0.52Ti0.48)O3/SrRuO3+Heterostructures.">Nonvolatile Electronic Writing of Epitaxial Pb(Zr0.52Ti0.48)O3/SrRuO3 Heterostructures.</a> Science. 276, 1100-1103 (1997).</li><li>Bi, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term='Water-cycle'+mechanism+for+writing+and+erasing+nanostructures+at+the+LaAlO3/SrTiO3+interface.">'Water-cycle' mechanism for writing and erasing nanostructures at the LaAlO3/SrTiO3 interface.</a> Applied Physics Letters. 97, 173110 (2010).</li><li>Cheng, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anomalous+Transport+in+Sketched+Nanostructures+at+the+LaAlO3/SrTiO3+Interface.">Anomalous Transport in Sketched Nanostructures at the LaAlO3/SrTiO3 Interface.</a> Phys Rev X. 3, 011021 (2013).</li><li>Veazey, J. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonlocal+current-voltage+characteristics+of+gated+superconducting+sketched+oxide+nanostructures.">Nonlocal current-voltage characteristics of gated superconducting sketched oxide nanostructures.</a> Europhys Lett. 103, 57001 (2013).</li><li>Veazey, J. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxide-based+platform+for+reconfigurable+superconducting+nanoelectronics.">Oxide-based platform for reconfigurable superconducting nanoelectronics.</a> Nanotechnology. 24, 375201 (2013).</li><li>Irvin, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anomalous+High+Mobility+in+LaAlO3/SrTiO3+Nanowires.">Anomalous High Mobility in LaAlO3/SrTiO3 Nanowires.</a> Nano Letters. 13, 364-368 (2013).</li><li>Salaita, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Massively+Parallel+Dip&#8211;Pen+Nanolithography+with+55+Two-Dimensional+Arrays.">Massively Parallel Dip&#8211;Pen Nanolithography with 55 Two-Dimensional Arrays.</a> Angewandte Chemie. 118, 7378-7381 (2006).</li><li>Li, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parallel+Conductive-AFM+Lithography+on+LaAlO3/SrTiO3+Interfaces.">Parallel Conductive-AFM Lithography on LaAlO3/SrTiO3 Interfaces.</a> Ieee T Nanotechnol. 12, 518-520 (2013).</li><li>Cen, C., Bogorin, D. F., Levy, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+activation+and+quantum+field+emission+in+a+sketch-based+oxide+nanotransistor.">Thermal activation and quantum field emission in a sketch-based oxide nanotransistor.</a> Nanotechnology. 21, 475201 (2010).</li><li>Bogorin, D. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoscale+rectification+at+the+LaAlO3/SrTiO3+interface.">Nanoscale rectification at the LaAlO3/SrTiO3 interface.</a> Applied Physics Letters. 97, 013102 (2010).</li><li>Cheng, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sketched+Oxide+Single-Electron+Transistor.">Sketched Oxide Single-Electron Transistor.</a> Nature Nanotech. 6, 343-347 (2011).</li><li>Joshua, A., Ruhman, J., Pecker, S., Altman, E., Ilani, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gate-tunable+polarized+phase+of+two-dimensional+electrons+at+the+LaAlO3/SrTiO3+interface.">Gate-tunable polarized phase of two-dimensional electrons at the LaAlO3/SrTiO3 interface.</a> PNAS. 110, 9633 (2013).</li><li>Irvin, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rewritable+Nanoscale+Oxide+Photodetector.">Rewritable Nanoscale Oxide Photodetector.</a> Nature Photon. 4, 849-852 (2010).</li><li>Ma, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Broadband+Terahertz+Generation+and+Detection+at+10+nm+Scale.">Broadband Terahertz Generation and Detection at 10 nm Scale.</a> Nano Letters. 13, 2884-2888 (2013).</li></ol>

The authors have nothing to disclose.

Successful creation of nanostructures depends on several critical steps. It is important that the LAO/STO samples are grown with a thickness that is known to be at the boundary between the insulating and conductive phase. (Details of sample growth fall outside the scope of this paper, but are crucial for overall success.) Second, it is important to have relative humidity within the range 25-45% for successful c-AFM writing. Values below 25% are unlikely to produce conductive nanostructures, while too high humidity will generally produce uncontrollably large features. Also, temperature control of the AFM is important if the c-AFM tip needs to achieve precise registry over long periods of time. Once the nanostructures are created, they must be placed in a vacuum environment if experiments lasting longer than a few hours are to be performed. For the experiments described here, the structure is created and within minutes transferred to a vacuum environment.
It is recommend before writing that a &#8220;writing test&#8221; be performed on all relevant electrodes. In such a test, two virtual electrodes are first created, and a single nanowire is written while simultaneously monitoring the conductance. A similar test of erasure can be performed by &#8220;cutting&#8221; the nanowire shortly afterwards. If the nanostructure is decaying rapidly, the issue is most likely due either to the interfacial contacts or the canvas itself. To distinguish between these two effects, a four-terminal measurement of the conductance should be performed, and the two-terminal conductance should be compared with the four-terminal conductance as a function of time. If the two-terminal conductance is decaying more rapidly than the four-terminal conductance, then the issue is related to the electrical contacts to the interface. If the four-terminal conductance is decaying at a comparable rate, then most likely the canvas is not suitable and should be replaced.
There are natural limitations of the current method for creating nanostructures. Specifically, the writing speed for the smallest devices is limited to a few hundred nanometers per second. Speeds far above that value lead to unpredictable results. Use of parallel writing techniques are possible27,28, but are not highly developed and have their own drawbacks. The size of nanostructures that can be created is naturally limited by the scan range of the AFM being used. A high-quality AFM with closed-loop feedback in the two scan directions is highly recommended. Tracking of point-like objects on the sample surface should be performed to monitor temporal drift of the sample.
Once creation of conductive nanostructures at oxide interfaces has been mastered, there are a wide range of experimental directions that can be explored. Using this technique, a wide variety of nanostructures and devices have already been demonstrated, including nanowires18, tunnel barriers29, rectifying junctions30, field-effect transistors18, single-electron transistors31, superconducting nanowires32, nanoscale optical detectors33, and nanoscale THz emitters and detectors34.

Eterostrutture Ossido 1-5 mostrano una notevole varietà di fenomeni fisici emergenti che sono sia scientificamente interessante e potenzialmente utile per le applicazioni 4. In particolare, l&#39;interfaccia tra LaAlO 3 (LAO) e SrTiO 3 (STO) 6 può esibire isolante, conduzione, superconduttori 7, ferroelettrici come 8 e 9 comportamento ferromagnetico. Nel 2006, Thiel et al hanno dimostrato 10 che c&#39;è una transizione netta isolante-metallo come lo spessore dello strato LAO viene aumentata, con uno spessore critico di 4 celle unitarie (4uc). Successivamente è stato dimostrato che le strutture 3uc-LAO/STO presentano una transizione isteresi che può essere controllato localmente con un conduttore microscopio a forza atomica (AFM-c) sonda 11. Le proprietà delle interfacce ossido come LaAlO 3/3 SrTiO dipendono dalla assenza o presenza di condurreelettroni all&#39;interfaccia. Questi elettroni possono essere controllate utilizzando migliori elettrodi di gate 12,13, schiena Portone 10, superficie adsorbati 14 strati ferroelettrici 15,16 e c-AFM litografia 11. Una caratteristica unica di c-AFM litografia è che molto piccole caratteristiche nanoscala possono essere creati. Gating top elettrico, in combinazione con la reclusione bidimensionale, viene spesso utilizzato per creare punti quantici di semiconduttori III-V 17. In alternativa, nanofili semiconduttori quasi-unidimensionali possono essere gated elettricamente dalla vicinanza. I metodi per produrre queste strutture sono in termini di tempo e generalmente irreversibile. Al contrario, la tecnica litografia c-AFM è reversibile, nel senso che una nanostruttura può essere creato per un esperimento, e poi &quot;cancellata&quot; (simile ad una lavagna). Generalmente, scrittura c-AFM viene eseguita con tensioni positive applicate alla punta AFM, mentre, cancellandoviene eseguita utilizzando tensioni negative. Il tempo necessario per creare una particolare struttura dipende dalla complessità del dispositivo, ma è di solito meno di 30 min; maggior parte del tempo viene speso cancellando la tela. La risoluzione spaziale tipica è di circa 10 nanometri, ma con la sintonizzazione corretta caratteristiche piccolo come 2 nanometri possono essere creati 18. Una descrizione dettagliata della procedura di fabbricazione su scala nanometrica segue. Il dettaglio fornito qui dovrebbe essere sufficiente a consentire esperimenti simili da eseguire da ricercatori interessati. Il metodo qui descritto presenta numerosi vantaggi rispetto agli approcci litografiche tradizionali utilizzati per creare nanostrutture elettronici nei semiconduttori. Il metodo di litografia c-AFM qui descritto è parte di una classe molto più ampia di iniziative litografia a base di scansione a sonda, tra cui la scansione di ossidazione anodica 19, dip-pen nanolitografia 20, patterning piezoelettrico21, e così via. La tecnica c-AFM qui descritto, insieme con l&#39;uso di interfacce ossido nuovi, può produrre alcune delle strutture elettroniche massima precisione con una varietà senza precedenti di proprietà fisiche.

<table border="0" cellpadding="0" cellspacing="0" width="889">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:165px;">Name</td>
			<td style="width:169px;">Company</td>
			<td style="width:108px;">Catalog Number</td>
			<td style="width:447px;">Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Contact Aligner</td>
			<td>Karl-Suss</td>
			<td>MA6</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Spinner</td>
			<td>Solitec</td>
			<td>5110C</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ion Mill</td>
			<td>Commonwealth Scientific</td>
			<td>8C</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sputtering System</td>
			<td>Leybold-Heraeus</td>
			<td>Z-650</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Barrel Etcher</td>
			<td>Branson/IPC</td>
			<td>3000C</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Wire Bonder</td>
			<td>Westbond</td>
			<td>7700E</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">AFM</td>
			<td>Asylum Research</td>
			<td>MFP-3D</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Dilution Refrigerator</td>
			<td>Quantum Design</td>
			<td>P850</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ultrasonic Wash Machine</td>
			<td>Fisher Scientific</td>
			<td>15-335-6</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Current Amplifier</td>
			<td>Femto</td>
			<td>DLPCA-200</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Materials</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">LaAlO3/SrTiO3</td>
			<td>Prof. Chang-Beom Eom</td>
			<td>N/A</td>
			<td>5mm x 1mm with ~3.4 unit cells of LAO (See Reference 18)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Photoresist</td>
			<td>AZ Electronic Materials</td>
			<td>P4210</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Developer</td>
			<td>AZ Electronic Materials</td>
			<td>400K</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Acetone</td>
			<td>Fisher Scientific</td>
			<td>A929SK-4</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Isopropyl Alcohol</td>
			<td>Fisher Scientific</td>
			<td>A459-1</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Deionized Water</td>
			<td>Fisher Scientific</td>
			<td>23-290-065</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Gold Wire</td>
			<td>DuPont</td>
			<td>5771</td>
			<td>1 mil diameter</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Chip Carrier</td>
			<td>NTK Technologies</td>
			<td>IRK28F1-5451D</td>
			<td></td>
		</tr>
	</tbody>
</table>

writing and low-temperature characterization of oxide nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

I risultati mostrati qui sono rappresentative del comportamento dei trasporti che può essere esposto da questa classe di nanostrutture, ed è stato descritto altrove in dettaglio 23-26. In questo esempio, una cavità nanofili è stato costruito (figura 4) da una eterostruttura LAO cella 3,3 unità / STO. Percorsi conduttivi (in verde) sono tipicamente 10 nm di larghezza, come determinato dal nanowire &quot;tagliando&quot; esperimenti 11. La velocità di punta e la tensione per ogni segmento è configurabile in modo indipendente dal pannello di litografia anteriore (Figura 4B), così come la velocità di scrittura di punta. &quot;Elettrodi virtuali&quot; che si interfacciano con i contatti interfacciali assicurano che vi sia una connessione elettrica altamente conduttivo sulle nanostrutture. Dopo la nanostruttura è scritto, è trasferito al frigorifero diluizione. L&#39;esposizione alla luce o al di sotto di 550 nm produrrà photoconduction indesiderato, quindi è important trasferire il dispositivo al buio o con l&#39;ausilio di un rosso &quot;camera oscura&quot; luce (Figura 5A). I collegamenti elettrici devono essere effettuate a temperatura ambiente, e come con la maggior parte delle nanostrutture di semiconduttori, grande attenzione dovrebbero essere prese quando si cambia i collegamenti elettrici a temperature criogeniche. Se i dispositivi vengono sottoposti a scariche elettrostatiche, molto probabilmente diventerà isolante. Sorprendentemente, la funzionalità può essere recuperato da &quot;bicicletta&quot; la temperatura di 300 K e raffreddamento di nuovo. Durante cooldown, è di routine per monitorare la resistenza a due terminali, e anche la resistenza a quattro terminali, in funzione della temperatura. Per queste misure una tensione alternata (tipicamente ~ 1 mV) viene applicato ad una bassa frequenza (&lt;10 Hz) a uno degli elettrodi, mentre la corrente alternata è misurata con un amplificatore di transimpedenza. Lock-in demodulazione e il filtraggio viene eseguita utilizzando un amplificatore lock-in casa-sviluppato. Il cu acrrent viene monitorata in funzione della temperatura (Figura 5B). Una volta che il dispositivo viene raffreddata alla temperatura di base del frigorifero diluizione (50 mK), misure di trasporto a quattro terminali vengono eseguite (Figura 5C). Per le misurazioni di corrente viene prelevato attraverso il canale principale del dispositivo, mentre la tensione ai capi del dispositivo viene misurata simultaneamente. Invece di misurare con un amplificatore lock-in, un pieno corrente-tensione (IV) traccia viene misurata. Questo metodo contiene più informazioni e la conduzione differenziale può essere calcolato tramite differenziazione numerica. Per il particolare dispositivo, la conduzione differenziale è misurata in funzione del lato sg-gate tensione V. Questa porta consente il potenziale chimico del dispositivo da modificare. Il trasporto attraverso il dispositivo mostra una forte dipendenza non monotona, indicando regioni in cui Coulomb blocco avviene per i valori più piccoli, e strong la superconduttività per i più grandi valori di V sg. Dettagli sulla interpretazione fisica per questa classe di dispositivi saranno descritte altrove. <img alt="Figura 1" src="/files/ftp_upload/51886/51886fig1highres.jpg" /> .. Figura 1, fasi di lavorazione fotolitografiche Fase 1: centrifuga fotosensibile. Fase 2: esporre photoresist utilizzando la maschera allineatore. Fase 3: sviluppare fotosensibile. Fase 4: fresatura di ioni. Fase 5: DC sputtering a depositare Ti e Au. Fase 6: lift-off. Fase 7: depositare il secondo strato. Fase 8: pulizia plasma. <img alt="Figura 2" src="/files/ftp_upload/51886/51886fig2highres.jpg" /> Figura 2. Immagini di lithographically fantasia eterostrutture LAO / STO. (A) Immagine che mostra 5mm x 5mm campione filo legato a un chip carrier. (B)<html> Ottico d&#39;immagine che mostra i rilievi di legame e una delle tele. (C) Close-up di un&#39;unica tela. <a href="https://www.jove.com/files/ftp_upload/51886/51886fig2highres.jpg" target="_blank">cliccate qui per vedere una versione più grande di questa figura.</a> <img alt="Figura 3" src="/files/ftp_upload/51886/51886fig3highres.jpg" /> Figura 3. (A) progettazione informale dei LAO / STO nanostruttura. (B) disposizione precisa di nanostrutture utilizzando un open-source di grafica vettoriale scalabile (SVG) montaggio. <img alt="Figura 4" src="/files/ftp_upload/51886/51886fig4highres.jpg" /> Figura 4. (A) litografia pannello anteriore per c-AFM patterning. (B) la posizione e la tensione di punta c-AFM Screenshot dal simulatore 3D che mostra.w.jove.com/files/ftp_upload/52058/52058fig4large.jpg &quot;target =&quot; _blank &quot;&gt; Clicca qui per vedere una versione più grande di questa figura. <img alt="Figura 5" src="/files/ftp_upload/51886/51886fig5highres.jpg" /> Figura 5. (A) LAO / STO nanostruttura essendo inserito in diluizione frigorifero. (B) Controllo di resistenza campione viene raffreddato da 300 K a 50 mK. (C) Controllo di conduttanza differenziale a quattro terminali di dispositivo in funzione della Vsg tensione cancello laterale e tensione ai capi del dispositivo (V4T). Grafico di intensità visualizzato in unità di siemens (S), e le tensioni sono visualizzati in unità di volt (V).

Watch this Scientific Journal Video about Writing and Low-Temperature Characterization of Oxide Nanostructures at JoVE.com

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

Scrittura e bassa temperatura Caratterizzazione di nanostrutture di ossido

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

writing-and-low-temperature-characterization-of-oxide-nanostructures

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9.9K Views.  University of Pittsburgh. Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

Video: Writing and Low-Temperature Characterization of Oxide Nanostructures

A Method to Fabricate Disconnected Silver Nanostructures in 3D

The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.1,2 Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.3-7 However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.8 Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,9 such as coupled metal dot10,11or coupled metal rod12,13 resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses.
In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can form structures in the bulk of a material rather than on its surface.
Most work on 3D direct metal writing has focused on creating self-supported metal structures.14-16 The method described here yields sub-micrometer silver structures that do not need to be self-supported because they are embedded inside a matrix. A doped polymer matrix is prepared using a mixture of silver nitrate (AgNO3), polyvinylpyrrolidone (PVP) and water (H2O). Samples are then patterned by irradiation with an 11-MHz femtosecond laser producing 50-fs pulses. During irradiation, photoreduction of silver ions is induced through nonlinear absorption, creating an aggregate of silver nanoparticles in the focal region. Using this approach we create silver patterns embedded in a doped PVP matrix. Adding 3D translation of the sample extends the patterning to three dimensions.

Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.

Un metodo per fabbricare nanostrutture d&#39;argento disconnesse in 3D

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

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Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

Probing e mapping superfici di elettrodo nelle celle di combustibile ad ossidi solidi

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen ...

Visible-light Induced Reduction of Graphene Oxide Using Plasmonic Nanoparticle

Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using visible light irradiation with plasmonic nanoparticles. The plasmonic nanoparticle is used to improve the reduction efficiency of GO. It only takes 30 min&#160;at RT by illuminating the solutions with Xe-lamp, the r-GO solutions can be obtained by completely removing gold nanoparticles through simple centrifugation step. The spherical gold nanoparticles (AuNPs) as compared to the other nanostructures is the most suitable plasmonic nanostructure for r-GO preparation. The reduced graphene oxide prepared using visible light and AuNPs was equally qualitative as chemically reduced graphene oxide, which was supported by various analytical techniques such as UV-Vis spectroscopy, Raman spectroscopy, powder XRD and XPS. The reduced graphene oxide prepared with visible light shows excellent quenching properties over the fluorescent molecules modified on ssDNA and excellent fluorescence recovery for target DNA detection. The r-GO prepared by recycled AuNPs is found to be of same quality with that of chemically reduced r-GO. The use of visible light with plasmonic nanoparticle demonstrates the good alternative method for r-GO synthesis.

A simple protocol for the preparation of reduced graphene oxide using visible light and plasmonic nanoparticle is described.

Luce visibile riduzione indotta di grafene ossido Usando nanoparticelle plasmoniche

Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using ...

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor performance, which suggest a new direction for the development of next-generation ultrathin and flexible photonic and electronic devices. Enhanced luminescence quantum efficiency has been widely observed in these atomically thin 2D crystals. However, dimension effects beyond quantum confinement thicknesses or even at the micrometer scale are not expected and have rarely been observed. In this study, molybdenum diselenide (MoSe2) layer crystals with a thickness range of 6-2,700 nm were fabricated as two- or four-terminal devices. Ohmic contact formation was successfully achieved by the focused-ion beam (FIB) deposition method using platinum (Pt) as a contact metal. Layer crystals with various thicknesses were prepared through simple mechanical exfoliation by using dicing tape. Current-voltage curve measurements were performed to determine the conductivity value of the layer nanocrystals. In addition, high-resolution transmission electron microscopy, selected-area electron diffractometry, and energy-dispersive X-ray spectroscopy were used to characterize the interface of the metal&#8211;semiconductor contact of the FIB-fabricated MoSe2 devices. After applying the approaches, the substantial thickness-dependent electrical conductivity in a wide thickness range for the MoSe2-layer semiconductor was observed. The conductivity increased by over two orders of magnitude from 4.6 to 1,500 &#937;&#8722;1 cm&#8722;1, with a decrease in the thickness from 2,700 to 6 nm. In addition, the temperature-dependent conductivity indicated that the thin MoSe2 multilayers exhibited considerably weak semiconducting behavior with activation energies of 3.5-8.5 meV, which are considerably smaller than those (36-38 meV) of the bulk. Probable surface-dominant transport properties and the presence of a high surface electron concentration in MoSe2 are proposed. Similar results can be obtained for other layer semiconductor materials such as MoS2 and WS2.

We describe the approaches for the device fabrication and electrical characterization of molybdenum diselenide (MoSe2) layer semiconductor nanostructures with different thicknesses. In addition, the fabrication of ohmic contacts for MoSe2-layer nanocrystals by the focused-ion beam deposition method using platinum (Pt) as a contact metal is described.

Ohmico Fabrication contatto con una tecnica Focused Ion Beam-e caratterizzazione elettrica per strato semiconduttore Nanostrutture

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor ...

Fabrication of Low Temperature Carbon Nanotube Vertical Interconnects Compatible with Semiconductor Technology

We demonstrate a method for the low temperature growth (350 &#176;C) of vertically-aligned carbon nanotubes (CNT) bundles on electrically conductive thin-films. Due to the low growth temperature, the process allows integration with modern low-&#954; dielectrics and some flexible substrates. The process is compatible with standard semiconductor fabrication, and a method for the fabrication of electrical 4-point probe test structures for vertical interconnect test structures is presented. Using scanning electron microscopy the morphology of the CNT bundles is investigated, which demonstrates vertical alignment of the CNT and can be used to tune the CNT growth time. With Raman spectroscopy the crystallinity of the CNT is investigated. It was found that the CNT have many defects, due to the low growth temperature. The electrical current-voltage measurements of the test vertical interconnects displays a linear response, indicating good ohmic contact was achieved between the CNT bundle and the top and bottom metal electrodes. The obtained resistivities of the CNT bundle are among the average values in the literature, while a record-low CNT growth temperature was used.

A method for the growth of low temperature vertically-aligned carbon nanotubes, and the subsequent fabrication of vertical interconnect electrical test structures using semiconductor fabrication is presented.

Fabbricazione di bassa temperatura Nanotubi di carbonio interconnessioni verticali Compatibile con la tecnologia Semiconductor

We demonstrate a method for the low temperature growth (350 &#176;C) of vertically-aligned carbon nanotubes (CNT) bundles on electrically conductive ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

Integrazione di luce Trapping Argento Nanostrutture in silicio microcristallino idrogenato celle solari tramite bonifico stampa

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Writing Bragg Gratings in Multicore Fibers

Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong suppression at a single wavelength requires that all cores have matching transmission profiles. These gratings cannot be inscribed using the same method as for single-core fibers because the curved surface of the cladding acts as a lens, focusing the incoming UV laser beam and causing variations in exposure between cores. Therefore we use an additional optical element to ensure that the beam shape does not change while passing through the cross-section of the multicore fiber. This consists of a glass capillary tube which has been polished flat on one side, which is then placed over the section of the fiber to be inscribed. The laser beam enters the fiber through the flat surface of the capillary tube and hence maintains its original dimensions. This paper demonstrates the improvements in core-to-core uniformity for a 7-core fiber using this method. The technique can be generalized to larger multicore fibers.

We describe a technique for inscribing identical fiber Bragg gratings into each core of a multicore fiber. This is achieved by introducing an additional surface into the optical path to mitigate lensing by the curved surface of the fiber cladding.

Scrivendo di Bragg in fibra Multicore

Fiber Bragg gratings in multicore fibers can be used as compact and robust filters in astronomical and other research and commercial applications. Strong ...

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (&#181;PAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

The study demonstrates the growth of iridium oxide-reduced graphene oxide (IrO2-RGO) nanohybrid thin films on irregular and rough screen-printed carbon substrate through a green electrochemical synthesis, and their implementation as a pH sensor with a patterned paper-fluidic platform.

Grafene ossido nanoibrido film sottile elettrodi serigrafati Iridium ossido-riduzione modificato come usa e getta di carta elettrochimica microfluidici pH Sensori

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

Metodi sperimentali avanzati per bassa temperatura magnetotrasporto Misura di nuovi materiali

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

Fabrication and Characterization of Superconducting Resonators

Superconducting microwave resonators are of interest for a wide range of applications, including for their use as microwave kinetic inductance detectors (MKIDs) for the detection of faint astrophysical signatures, as well as for quantum computing applications and materials characterization. In this paper, procedures are presented for the fabrication and characterization of thin-film superconducting microwave resonators. The fabrication methodology allows for the realization of superconducting transmission-line resonators with features on both sides of an atomically smooth single-crystal silicon dielectric. This work describes the procedure for the installation of resonator devices into a cryogenic microwave testbed and for cool-down below the superconducting transition temperature. The set-up of the cryogenic microwave testbed allows one to do careful measurements of the complex microwave transmission of these resonator devices, enabling the extraction of the properties of the superconducting lines and dielectric substrate (e.g., internal quality factors, loss and kinetic inductance fractions), which are important for device design and performance.

Superconducting microwave resonators are of interest for detection of light, quantum computing applications and materials characterization. This work presents a detailed procedure for fabrication and characterization of superconducting microwave resonator scattering parameters.

Fabbricazione e caratterizzazione di superconduttori risonatori

Superconducting microwave resonators are of interest for a wide range of applications, including for their use as microwave kinetic inductance detectors ...