Name: radio frequency magnetron sputtering of gdba2cu3o7&#8722;&#948;/ la0.67sr0.33mno3 quasi-bilayer films on srtio3 (sto) single-crystal substrates
Uploaded: 2019-04-12T12:30:00
Description: Watch this Scientific Journal Video about Radio Frequency Magnetron Sputtering of GdBa2Cu3O7âˆ'Î´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates at JoVE.com

This work was supported by the National Natural Science Foundation of China (No. 51502168; No.11504227) and the Shanghai Municipal Natural Science Foundation (No.16ZR1413600).The authors gratefully thank the Instrumental Analysis Center of Shanghai Jiao Tong University and Ma-tek analytical lab for competent technical assistance.

1. Substrate and Target Preparation
NOTE: This section describes the preparation of the sputter deposition chamber and the single crystal SrTiO3 (STO) substrates.
<ol>
	<li>Use 10 mm x 10 mm SrTiO3 (STO) single-crystal substrates during the RF magnetron sputtering process.</li>
	<li>Sequentially clean the substrates in isopropanol and deionized water for 10 min each at room temperature in ultrasonic bath. Then dry the substrates with nitrogen, which is for uniform cover...

<ol>
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K., Khare, N., Pinto, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interface+engineering+using+ferromagnetic+nanoparticles+for+enhancing+pinning+in+YBa2Cu3O7-delta+thin+film.">Interface engineering using ferromagnetic nanoparticles for enhancing pinning in YBa2Cu3O7-delta thin film.</a> Journal of Applied Physics. 110 (11), (2011).</li><li>Casotti, D., 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=Ageing+effects+on+electrical+resistivity+of+Nb-doped+TiO2+thin+films+deposited+at+a+high+rate+by+reactive+DC+magnetron+sputtering.">Ageing effects on electrical resistivity of Nb-doped TiO2 thin films deposited at a high rate by reactive DC magnetron sputtering.</a> Applied Surface Science. 455, 267-275 (2018).</li><li>Li, 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=Preparation+of+single-phase+Ti2AlN+coating+by+magnetron+sputtering+with+cost-efficient+hot-pressed+Ti-Al-N+targets.">Preparation of single-phase Ti2AlN coating by magnetron sputtering with cost-efficient hot-pressed Ti-Al-N targets.</a> Ceramics International. 44 (14), 17530-17534 (2018).</li><li>Mahdhi, H., Djessas, K., Ben Ayadi, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+characteristics+of+Ca-doped+ZnO+thin+films+by+rf+magnetron+sputtering+at+low+temperature.">Synthesis and characteristics of Ca-doped ZnO thin films by rf magnetron sputtering at low temperature.</a> Materials Letters. 214, 10-14 (2018).</li><li>Shen, H., Wei, B., Zhang, D., Qi, Z., Wang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetron+sputtered+NbN+thin+film+electrodes+for+supercapacitors.">Magnetron sputtered NbN thin film electrodes for supercapacitors.</a> Materials Letters. 229, 17-20 (2018).</li><li>Sinnarasa, I., 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=Influence+of+thickness+and+microstructure+on+thermoelectric+properties+of+Mg-doped+CuCrO2+delafossite+thin+films+deposited+by+RF-magnetron+sputtering.">Influence of thickness and microstructure on thermoelectric properties of Mg-doped CuCrO2 delafossite thin films deposited by RF-magnetron sputtering.</a> Applied Surface Science. , 244-250 (2018).</li><li>Thi-Thuy-Nga, N., Chen, Y. -. 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Here we have demonstrated that this method can be used to prepare LSMO ferromagnetic nanoparticles of uniform distribution on SrTiO3 (STO) single-crystal substrates. The (Gd) BCO films also can be deposited on both bare and LSMO decorated STO substrate. With an appropriate adjustment of deposited parameters, such as growth temperatures and target-substrate distance, this method ought to be useful for deposited different kinds of magnetic and non-magnetic particles or layers, for example, CeO2, YSZ (...

The hole-doped manganite La0.67Sr0.33MnO3 (LSMO) have unique properties such as wide-band gaps, half-metallic ferromagnetism, and entangled electronic states, which provide extraordinary opportunities for potential spintronic applications1,2,3,4. Currently, many researchers are endeavoring to take advantage of the unique properties of LSMO to inhabit the vortex movement for high temperature superconducting (HTS) films, such as (RE) Ba2Cu3O7&#8722;&#948; films (REBCO, RE= rare-earth element)5,6,7,8,9,10,11,12. Nanoscale decoration of the substrate surfaces with ferromagnetic nanoparticles will provide well-defined sites for inducing magnetic pinning centers of expected density13,14. However, the ability to control the density and geometry of the nanoparticles on highly textured surfaces, such as on single-crystal substrates and highly textured metal substrates is very difficult. Most commonly, nanoparticles are synthesized and coated on surfaces using metal organic decomposition methods15, and pulsed laser deposition methods16,17. Although pulse laser deposition methods can provide nanoparticles coated on various substrates, it is difficult to realize large area homogeneous nanoparticles deposition. As for metal organic decomposition methods, they are proper for large area deposition of nanoparticles. However, the nanoparticles are often non-uniform and easily damaged by small physical stresses.
Among these techniques, RF-magnetron sputtering has many advantages. Sputtering has a high deposition rate, low cost, and a lack of toxic gas emission. Also, it is easy to expand to large scale area substrates18,19. This method provides single-step formation of La0.67Sr0.33MnO3 (LSMO) nanoparticles, and the nanoparticles are easy to be deposited on single-crystal substrates. RF magnetron sputtering can create large area nanoparticles uniformly on a diverse range of substrates, irrespective of surface texture, and surface roughness20.The particle control can be achieved by adjust sputtering time. Homogeneity can be achieved by adjust target-substrate distance. The disadvantage of RF-magnetron sputtering is its lower growth rate for some oxides21. In this approach, target atoms (or molecules) are sputtered out of the target by argon ion, and then nanoparticles are deposited on substrates in the vapor phase22. Nanoparticles formation occurs on the substrate in a single step23. This method is theoretically applicable to any materials including superconducting thin film, resistance film, semiconductor film, ferromagnetic thin film etc. However, to date, reports about protocols for depositing ferromagnetic nanoparticles are very scarce.
Here, we demonstrate the deposition of GdBa2Cu3O7&#8722;&#948;/La0.67Sr0.33MnO3 quasi-bilayer films on SrTiO3 (STO) single-crystal substrates by RF magnetron sputtering method. Two kinds of target materials, GdBa2Cu3O7&#8722;&#948; and La0.67Sr0.33MnO3 target are used in the process. SrTiO3 (STO) single-crystal substrates were coated with GdBa2Cu3O7&#8722;&#948;films and GdBa2Cu3O7&#8722;&#948;/La0.67Sr0.33MnO3 quasi-bilayer films.
In this protocol, GdBa2Cu3O7&#8722;&#948;/La0.67Sr0.33MnO3 Quasi-bilayer films are deposited with RF magnetron sputtering on STO (001) substrates. The target diameter is 60 mm and the distance between the target and substrates is about 10 cm. The heaters are bulbs positioned 1 cm above the substrates. The maximum temperature is 850&#176;C in this system. There are 5 different substrates in this system. RF magnetron sputtering GdBa2Cu3O7&#8722;&#948;/La0.67Sr0.33MnO3 quasi-bilayer films consists of two steps, which are the preparation of substrates and the RF magnetron sputtering process. A picture of the sputtering system is shown in Figure&#160;S1.

<table>
	<tbody>
		<tr>
			<td>Sputter Deposition System</td>
			<td>Shenyang scientific instruments Limited by Share Ltd</td>
			<td>Bespoke</td>
			<td></td>
		</tr>
		<tr>
			<td>SrTiO3 Single Crystal Substrate</td>
			<td>Hefei Ke crystal material technology Co., Ltd</td>
			<td>Single-sided epi-polished</td>
			<td>(001) orientation</td>
		</tr>
		<tr>
			<td>La0.67Sr0.33MnO3 sputtering target</td>
			<td>Hefei Ke crystal material technology Co., Ltd</td>
			<td>Bespoke</td>
			<td>60 mm diameter</td>
		</tr>
		<tr>
			<td>GdBa2Cu3O7&#8722;&#948; sputtering target</td>
			<td>Hefei Ke crystal material technology Co., Ltd</td>
			<td>Bespoke</td>
			<td>60 mm diameter</td>
		</tr>
		<tr>
			<td>Atomic Force Microscope</td>
			<td>Br&#252;ker</td>
			<td>Dimension Icon</td>
			<td></td>
		</tr>
		<tr>
			<td>X-ray Diffractometer</td>
			<td>Br&#252;ker</td>
			<td>D8 Discover</td>
			<td></td>
		</tr>
		<tr>
			<td>Physical Property Measurement System</td>
			<td>Quantum Design</td>
			<td>PPMS 9</td>
			<td></td>
		</tr>
	</tbody>
</table>

radio frequency magnetron sputtering of gdba2cu3o7&#8722;&#948;/ la0.67sr0.33mno3 quasi-bilayer films on srtio3 (sto) single-crystal substrates

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF) magnetron sputtering. LSMO nanoparticles were deposited with diameters from 10 to 20 nm and heights between 20 and 50 nm. At the same time, (Gd) Ba2Cu3O7&#8722;&#948; ((Gd) BCO) films were fabricated on both undecorated and LSMO nanoparticle decorated STO substrates using RF magnetron sputtering. This report also describes the properties of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 quasi-bilayer films structures (e.g., crystalline phase, morphology, chemical composition); magnetization, magneto-transport, and superconducting transport properties were also evaluated.

The thickness of (Gd) BCO films on both bare and LSMO decorated STO substrate was 500nm, which was measured by a surface profilometer. The film thickness was controlled by sputtering time. Figure 1a,b shows the AFM image of LSMO nanoparticle (sputtering time of 10 s) on 1.0 cm x 1.0 cm single-crystal STO substrates to prove that the LSMO nanoparticles grown on STO substrates uniformly. The surface and to measure the roughness of the films was...

Watch this Scientific Journal Video about Radio Frequency Magnetron Sputtering of GdBa2Cu3O7âˆ'Î´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates at JoVE.com

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7ÃƒÂ¢Ã‹â€ &#039;ÃƒÅ½ ´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates

Here, we present a protocol to grow LSMO nanoparticles and (Gd) BCO films on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF)-sputtering.

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio ...

This method can create the LSMO nanoparticles uniformly on a STO single-crystal substrate. Also, the GBCO film can be obtained through the same method in the same vacuum chamber. The main advantage of this technology is that LSMO nanoparticles with uniform size and high-quality superconducting GBCO film can be deposited in the same vacuum chamber.This method can provide insight into film deposition area, nanoparticle growth area, et cetera. It can also be applied to metal film deposition, metal nanoparticle deposition, et cetera. This method will allow researchers to become familiar with vacuum equipment and learn more about film growth technology.First, sequentially clean strontium titanium oxide single-crystal substrates in isopropanol and deionized water for 10 minutes each at room temperature in an ultrasonic bath. Then, dry the substrates with nitrogen. This promotes uniform covering of the substrate and good film adherence.Mount the 001-oriented STO substrates in substrate holders with silver powder conductive glue. Load the holders into a vacuum chamber. Mount an LSMO target in a magnetron injection gun, and then reassemble the gun.Test the resistance with an ohmmeter to avoid a short circuit between the magnetron and the surrounding shield. Then, close the vacuum chamber, and pump down. Once the vacuum is lower than one times 10 to the minus four pascals, heat the substrate to 850 degrees Celsius using a heating rate of 15 degrees Celsius per minute.Set the target substrate distance to eight centimeters. Next, set the mass flow controller to 10 standard cubic centimeters per minute of oxygen and five standard cubic centimeters per minute of argon as the working gas flow. Before deposition, pre-sputter the LSMO target for 20 minutes at 30 watts.To obtain a chamber pressure of 25 pascals, adjust the molecular pump splint valve. If the instant value becomes larger than 25 pascals, rotate it counterclockwise. If it becomes smaller than 25 pascals, rotate it clockwise.Following this, check that the substrate temperature remains at 850 degrees Celsius and is stable. Increase the power of the magnetron from 30 to 80 watts. After the plasma is stabilized, open the shutter and deposit LSMO on the heated substrate.Once the deposition is complete, close the shutter and shut off power to the magnetron. Then, close the gas valve, and shut off the heater power. After cooling the samples to room temperature, vent the chamber with dry nitrogen.Then, open the chamber, and remove the samples. Mount the gadolinium barium copper oxygen target in the magnetron injection gun, and then reassemble the gun. Deposit the gadolinium barium copper oxygen films as previously described, using similar conditions except for the sputtering time, which should be 30 minutes.Next, decrease the sample temperature to 500 degrees Celsius. Then, open the gas valve for oxygen to give a chamber pressure of 75, 000 pascals, and hold the samples at this temperature for one hour. After cooling the samples to room temperature, vent the chamber with dry nitrogen.Then, open the chamber, and remove the samples. The AFM image of an LSMO nanoparticle on STO substrates shows uniform growth. The XRD patterns of gadolinium barium copper oxygen films fabricated on undecorated and LSMO nanoparticle-decorated STO substrates are shown here.The superconducting transition temperature was close to 90.5 kelvin for the gadolinium barium copper oxygen film and 90.3 kelvin for the LSMO films, which indicates that the nanoparticles don't harm the superconducting property for the films. By comparison, the magnetization hysteresis loop area is much bigger, from zero to six tesla, at 30, 50, and 77 kelvin for films fabricated on LSMO-decorated substrates. The gadolinium barium copper oxygen film deposited on an LSMO-decorated substrate possesses a higher critical current density from 1.3 to six tesla at 30 kelvin and from zero to six tesla at 77 kelvin.At 30 kelvin, the decorated sample has a larger pinning force density above 1.3 tesla. At 77 kelvin, the density moved to a higher H value for the decorated sample. The angular dependence of the critical current density at 3 tesla and 77 kelvin for the LSMO-decorated film shows an increase along the c-axis, suggesting that it is more effective at a magnetic field orientation parallel to the c-axis direction.This method involves many steps and details, so visual demonstration is critical for understanding and mastering this method. After its development, this method makes it possible to deposit oxide films and nanoparticles, as well as metal films and nanoparticles. After its development, this method makes it possible to deposit oxide films and nanoparticles, as well as metal films and nanoparticles.

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Micropunching Lithography for Generating Micro- and Submicron-patterns on Polymer Substrates

Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of low weight, easy tailoring of properties and a wide spectrum of applications2,3. Due to sensitivity of conducting polymers to environmental conditions (e.g., air, oxygen, moisture, high temperature and chemical solutions), lithographic techniques present significant technical challenges when working with these materials4. For example, current photolithographic methods, such as ultra-violet (UV), are unsuitable for patterning the conducting polymers due to the involvement of wet and/or dry etching processes in these methods. In addition, current micro/nanosystems mainly have a planar form5,6. One layer of structures is built on the top surfaces of another layer of fabricated features. Multiple layers of these structures are stacked together to form numerous devices on a common substrate. The sidewall surfaces of the microstructures have not been used in constructing devices. On the other hand, sidewall patterns could be used, for example, to build 3-D circuits, modify fluidic channels and direct horizontal growth of nanowires and nanotubes.
A macropunching method has been applied in the manufacturing industry to create macropatterns in a sheet metal for over a hundred years. Motivated by this approach, we have developed a micropunching lithography method (MPL) to overcome the obstacles of patterning conducting polymers and generating sidewall patterns. Like the macropunching method, the MPL also includes two operations (Fig. 1): (i) cutting; and (ii) drawing. The "cutting" operation was applied to pattern three conducting polymers4, polypyrrole (PPy), Poly(3,4-ethylenedioxythiophen)-poly(4-styrenesulphonate) (PEDOT) and polyaniline (PANI). It was also employed to create Al microstructures7. The fabricated microstructures of conducting polymers have been used as humidity8, chemical8, and glucose sensors9. Combined microstructures of Al and conducting polymers have been employed to fabricate capacitors and various heterojunctions9,10,11. The "cutting" operation was also applied to generate submicron-patterns, such as 100- and 500-nm-wide PPy lines as well as 100-nm-wide Au wires. The "drawing" operation was employed for two applications: (i) produce Au sidewall patterns on high density polyethylene (HDPE) channels which could be used for building 3D microsystems12,13,14, and (ii) fabricate polydimethylsiloxane (PDMS) micropillars on HDPE substrates to increase the contact angle of the channel15.

A micropunching lithography approach is developed to generate micro- and submicron-patterns on top, sidewall and bottom surfaces of polymer substrates. It overcomes the obstacles of patterning conducting polymers and generating sidewall patterns. This method allows rapid fabrication of multiple features and is free of aggressive chemistry.

Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of ...

Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. From the measured surface, 3D topographic maps can be subsequently analyzed using a variety of software packages to extract the information that is needed.
In this article we describe how white light interferometry, and optical profilometry (OP) in general, combined with generic surface analysis software, can be used for materials science and engineering tasks. In this article, a number of applications of white light interferometry for investigation of surface modifications in mass spectrometry, and wear phenomena in tribology and lubrication are demonstrated. We characterize the products of the interaction of semiconductors and metals with energetic ions (sputtering), and laser irradiation (ablation), as well as ex situ measurements of wear of tribological test specimens.
Specifically, we will discuss:
<ol class="lroman">
	<li>Aspects of traditional ion sputtering-based mass spectrometry such as sputtering rates/yields measurements on Si and Cu and subsequent time-to-depth conversion.</li>
	<li>Results of quantitative characterization of the interaction of femtosecond laser irradiation with a semiconductor surface. These results are important for applications such as ablation mass spectrometry, where the quantities of evaporated material can be studied and controlled via pulse duration and energy per pulse. Thus, by determining the crater geometry one can define depth and lateral resolution versus experimental setup conditions.</li>
	<li>Measurements of surface roughness parameters in two dimensions, and quantitative measurements of the surface wear that occur as a result of friction and wear tests.</li>
</ol>
Some inherent drawbacks, possible artifacts, and uncertainty assessments of the white light interferometry approach will be discussed and explained.

White light microscope interferometry is an optical, noncontact and quick method for measuring the topography of surfaces. It is shown how the method can be applied toward mechanical wear analysis, where wear scars on tribological test samples are analyzed; and in materials science to determine ion beam sputtering or laser ablation volumes and depths.

In materials science and engineering it is often necessary to obtain quantitative measurements of surface topography with micrometer lateral resolution. ...

Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates

In recent years &pi;-conjugated organic semiconductors have emerged as the active material in a number of diverse applications including large-area, low-cost displays, photovoltaics, printable and flexible electronics and organic spin valves. Organics allow (a) low-cost, low-temperature processing and (b) molecular-level design of electronic, optical and spin transport characteristics. Such features are not readily available for mainstream inorganic semiconductors, which have enabled organics to carve a niche in the silicon-dominated electronics market. The first generation of organic-based devices has focused on thin film geometries, grown by physical vapor deposition or solution processing. However, it has been realized that organic nanostructures can be used to enhance performance of above-mentioned applications and significant effort has been invested in exploring methods for organic nanostructure fabrication.	
A particularly interesting class of organic nanostructures is the one in which vertically oriented organic nanowires, nanorods or nanotubes are organized in a well-regimented, high-density array. Such structures are highly versatile and are ideal morphological architectures for various applications such as chemical sensors, split-dipole nanoantennas, photovoltaic devices with radially heterostructured "core-shell" nanowires, and memory devices with a cross-point geometry. Such architecture is generally realized by a template-directed approach. In the past this method has been used to grow metal and inorganic semiconductor nanowire arrays. More recently &pi;-conjugated polymer nanowires have been grown within nanoporous templates. However, these approaches have had limited success in growing nanowires of technologically important &pi;-conjugated small molecular weight organics, such as tris-8-hydroxyquinoline aluminum (Alq3), rubrene and methanofullerenes, which are commonly used in diverse areas including organic displays, photovoltaics, thin film transistors and spintronics.	
Recently we have been able to address the above-mentioned issue by employing a novel "centrifugation-assisted" approach. This method therefore broadens the spectrum of organic materials that can be patterned in a vertically ordered nanowire array. Due to the technological importance of Alq3, rubrene and methanofullerenes, our method can be used to explore how the nanostructuring of these materials affects the performance of aforementioned organic devices. The purpose of this article is to describe the technical details of the above-mentioned protocol, demonstrate how this process can be extended to grow small-molecular organic nanowires on arbitrary substrates and finally, to discuss the critical steps, limitations, possible modifications, trouble-shooting and future applications.

We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.

In  recent years &pi;-conjugated  organic semiconductors have emerged as the active material in a number of  diverse applications including large-area, ...

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling immensely. However, in soft electronics, in which organic semiconductors play a critical role, the devices will be bent or folded repeatedly. The effect of bending on the crystal packing and thus the charge transport is crucial to the performance of the device. In this manuscript, we describe the protocol to bend a single crystal of 5,7,12,16-tetrachloro-6,13-diazapentacene (TCDAP) in the field-effect transistor configuration and to obtain reproducible I-V characteristics upon bending the crystal. The results show that bending a field-effect transistor prepared on a flexible substrate results in nearly reversible yet opposite trends in charge mobility, depending on the bending direction. The mobility increases when the device is bent toward the top gate/dielectric layer (upward, compressive state) and decreases when bent toward the crystal/substrate side (downward, tensile state). The effect of bending curvature was also observed, with greater mobility change resulting from higher bending curvature. It is suggested that the intermolecular &#960;-&#960; distance changes upon bending, thereby influencing the electronic coupling and the subsequent carrier transport ability.

This manuscript describes the bending process of an organic single crystal-based field-effect transistor to maintain a functioning device for electronic property measurement. The results suggest that bending causes changes in the molecular spacing in the crystal and thus in the charge hopping rate, which is important in flexible electronics.

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling ...

Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures

The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted much attention from the oxide electronics community. One of its hallmark features is the existence of a critical LAO thickness of 4 unit-cells (uc) for interfacial conductivity to emerge. Although electrostatic mechanisms have been proposed in the past to describe the existence of this critical thickness, the importance of chemical defects has been recently accentuated. Here, we describe the growth of metal/LAO/STO heterostructures in an ultra-high vacuum (UHV) cluster system combining pulsed laser deposition (to grow the LAO), magnetron sputtering (to grow the metal) and X-ray photoelectron spectroscopy (XPS). We study step by step the formation and evolution of the q2DES and the chemical interactions that occur between the metal and the LAO/STO. Additionally, magnetotransport experiments elucidate on the transport and electronic properties of the q2DES. This systematic work not only demonstrates a way to study the electrostatic and chemical interplay between the q2DES and its environment, but also unlocks the possibility to couple multifunctional capping layers with the rich physics observed in two-dimensional electron systems, allowing the fabrication of new types of devices.

Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures

We fabricate metal/LaAlO3/SrTiO3 heterostructures using a combination of pulsed laser deposition and in situ magnetron sputtering. Through magnetotransport and in situ X-ray photoelectron spectroscopy experiments, we investigate the interplay between electrostatic and chemical phenomena of the quasi two-dimensional electron gas formed in this system.

The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted much attention from the oxide ...

Generation and Coherent Control of Pulsed Quantum Frequency Combs

We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional states on-chip in a practical way have remained elusive due to the increasing complexity of the quantum circuitry needed to prepare and process such states. Here, we outline how high-dimensional, frequency-bin entangled, two-photon states can be generated at a stable, high generation rate by using a nested-cavity, actively mode-locked excitation of a nonlinear micro-cavity. This technique is used to produce pulsed quantum frequency combs. Moreover, we present how the quantum states can be coherently manipulated using standard telecommunications components such as programmable filters and electro-optic modulators. In particular, we show in detail how to accomplish state characterization measurements such as density matrix reconstruction, coincidence detection, and single photon spectrum determination. The presented methods form an accessible, reconfigurable, and scalable foundation for complex high-dimensional state preparation and manipulation protocols in the frequency domain.

A protocol is presented for the practical generation and coherent manipulation of high-dimensional frequency-bin entangled photon states using integrated micro-cavities and standard telecommunications components, respectively.

We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional ...

Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films

Droplet impact is a very common phenomenon in nature and attracts attention due to its aesthetic fascination and wide-ranging applications. Previous studies on flowing liquid films have neglected the contributions of spatial structures of waves to the impact outcome, while this has recently been shown to have a significant influence on the drop impact dynamics. In this report, we outline a step-by-step procedure to investigate the effect of periodic inlet forcing of a flowing liquid film leading to the production of spatiotemporally regular wave structures on drop impact dynamics. A function generator in connection with a solenoid valve is used to excite these spatiotemporally regular wave structures on the film surface while the impact dynamics of uniform-sized droplets are captured using a high-speed camera. Three distinct regions are then studied; viz. the capillary wave region preceding the large wave peak, the flat film region, and the wave hump region. The effects of important dimensionless quantities such as film Reynolds, drop Weber and Ohnesorge numbers parameterized by the film flow rate, drop speed, and drop size are also examined. Our results show interesting, hitherto undiscovered dynamics brought about by this application of film inlet forcing of the flowing film for both low and high inertia drops.

A protocol to study the contributions of waves to droplet impact dynamics on flowing liquid films is presented.

Droplet impact is a very common phenomenon in nature and attracts attention due to its aesthetic fascination and wide-ranging applications. Previous ...

Plasma-Assisted Molecular Beam Epitaxy Growth of Mg3N2 and Zn3N2 Thin Films

This article describes a procedure for growing Mg3N2 and Zn3N2 films by plasma-assisted molecular beam epitaxy (MBE). The films are grown on 100 oriented MgO substrates with N2 gas as the nitrogen source. The method for preparing the substrates and the MBE growth process are described. The orientation and crystalline order of the substrate and film surface are monitored by the reflection high energy electron diffraction (RHEED) before and during growth. The specular reflectivity of the sample surface is measured during growth with an Ar-ion laser with a wavelength of 488 nm. By fitting the time dependence of the reflectivity to a mathematical model, the refractive index, optical extinction coefficient, and growth rate of the film are determined. The metal fluxes are measured independently as a function of the effusion cell temperatures using a quartz crystal monitor. Typical growth rates are 0.028 nm/s at growth temperatures of 150 &#176;C and 330 &#176;C for Mg3N2 and Zn3N2 films, respectively.

Plasma-Assisted Molecular Beam Epitaxy Growth of Mg3N2 and Zn3N2 Thin Films

This article describes the growth of epitaxial films of Mg3N2 and Zn3N2 on MgO substrates by plasma-assisted molecular beam epitaxy with N2 gas as the nitrogen source and optical growth monitoring.

This article describes a procedure for growing Mg3N2 and Zn3N2 films by plasma-assisted molecular beam epitaxy (MBE). The films are grown on 100 oriented ...

Procedure for the Transfer of Polymer Films Onto Porous Substrates with Minimized Defects

The fabrication of devices containing thin film composite membranes necessitates the transfer of these films onto the surfaces of arbitrary support substrates. Accomplishing this transfer in a highly controlled, mechanized, and reproducible manner can eliminate the creation of macroscale defect structures (e.g., tears, cracks, and wrinkles) within the thin film that compromise device performance and the usable area per sample. Here, we describe a general protocol for the highly controlled and mechanized transfer of a polymeric thin film onto an arbitrary porous support substrate for eventual use as a water filtration membrane device. Specifically, we fabricate a block copolymer (BCP) thin film on top of a sacrificial, water-soluble poly(acrylic acid) (PAA) layer and silicon wafer substrate. We then utilize a custom-designed, 3D-printed transfer tool and drain chamber system to deposit, lift-off, and transfer the BCP thin film onto the center of a porous anodized aluminum oxide (AAO) support disc. The transferred BCP thin film is shown to be consistently placed onto the center of the support surface due to the guidance of the meniscus formed between the water and the 3D-printed plastic drain chamber. We also compare our mechanized transfer-processed thin films to those that have been transferred by hand with the use of tweezers. Optical inspection and image analysis of the transferred thin films from the mechanized process confirm that little-to-no macroscale inhomogeneities or plastic deformations are produced, as compared to the multitude of tears and wrinkles produced from manual transfer by hand. Our results suggest that the proposed strategy for thin film transfer can reduce defects when compared to other methods across many systems and applications.

We present a procedure for highly controlled and wrinkle-free transfer of block copolymer thin films onto porous support substrates using a 3D-printed drain chamber. The drain chamber design is of general relevance to all procedures involving transfer of macromolecular films onto porous substrates, which is normally done by hand in an irreproducible fashion.

The fabrication of devices containing thin film composite membranes necessitates the transfer of these films onto the surfaces of arbitrary support ...

Calibration of Vector Network Analyzer for Measurements in Radio Frequency Propagation Channels

In situ measurements of radio frequency (RF) spectrum activity provide insight into the physics of radio frequency wave propagation and validate existing and new spectrum propagation models. Both of these parameters are essential to supporting and preserving interference-free spectrum sharing, as spectrum use continues to increase. It is vital that such propagation measurements are accurate, reproducible, and free of artifacts and bias. Characterizing the gains and losses of components used in these measurements is vital to their accuracy. A vector network analyzer (VNA) is a well-established, highly accurate, and versatile piece of equipment that measures both magnitude and phase of signals, if properly calibrated. This article details the best practices for calibrating a VNA. Once calibrated, it can be used to accurately measure components of a correctly configured propagation measurement (or channel sounding) system or can be used as a measurement system itself.

This protocol describes best practices for calibrating a vector network analyzer prior to use as an accurate instrument, intended to measure components of a radio frequency propagation measurement test system.

In situ measurements of radio frequency (RF) spectrum activity provide insight into the physics of radio frequency wave propagation and validate existing ...