This work was funded by the European Research Council (ERC) under the European Union&#8217;s Horizon 2020 research and innovation program (No.803004).

1. Preparation of the solution
<ol>
	<li>Prepare a solution containing prehydrolyzed tetraethyl orthosilicate (TEOS) 18 h before the production of the gel films in a fume hood in which a lab balance and a magnetic stirrer are placed.
	<ol>
		<li>Add 0.7 g of polyethylene glycol hexadecyl ether (Brij-58) and 23.26 g of ethanol into 50 mL bottle and close the lid of the bottle and stir it until the Brij is completely dissolved.</li>
		<li>Add 1.5 g of HCl 35% into the flask in step 1.1.1, close it and stir for 20 s.</li>
		<li>Add 4.22 g of TEOS to the flask in step 1.1.2, close it and let it stir for 18 h.</li>
	</ol>
	</li>
	<li>Preparation of 1 M aqueous solution of Sr2+ just before the production of the gel films because a matured solution is susceptible to re-precipitate in form of Sr salt.
	<ol>
		<li>Weigh 2.67 g of SrCl2&#183;6H2O in a 10 mL volumetric flask.</li>
		<li>Add 10 mL ultrapure water (e.g., Milli-Q) up to 10 mL into the flask in step 1.2.1 and close the flask with a plastic cap and gently shake the flask to dissolve the strontium chloride.</li>
	</ol>
	</li>
	<li>Add 275 &#181;L of the 1 M aqueous solution of Sr2+ into the 10 mL bottle containing the solution that was prepared in step 1.1 and stir the solution for 10 min.</li>
</ol>
2. Preparation of polydimethylsiloxane (PDMS) templates
<ol>
	<li>Preparation of PDMS solution after step 1.3.
	<ol>
		<li>Mix 1 part of the curing agent with 10 parts of the elastomer in a beaker on the balance. Stir the mixture with a glass stick until obtaining a homogeneous distribution of bubbles and remove it in a vacuum chamber.</li>
	</ol>
	</li>
	<li>Replicate the silicon master using the PDMS solution. Notice that for this work, we used a silicon patterned master composed of pillars with diameters, height, and separation distance of 1 &#181;m.
	<ol>
		<li>Put the silicon master with the structured face up in a plastic box and fill the box with the PDMS solution.</li>
		<li>Introduce the plastic box into the furnace at 70 &#176;C for 2 h to obtain a solid PDMS template.</li>
		<li>Separate the PDMS template and the silicon master. Cut the PDMS template to the desired size using a blade and keep it in a clean box.</li>
	</ol>
	</li>
</ol>
3. Gel film deposition on SOI (100) substrates by dip-coating
<ol>
	<li>Preparation of the substrates
	<ol>
		<li>Prepare 2 cm x 6 cm sized substrates by cutting a 2-inch p-type SOI wafer with the thickness of 2/0.5/0.67 &#181;m (Si/SiO2/Si) in a direction parallel or perpendicular to the wafer flat using a diamond tip. Notice that the conductivity of the silicon device layer must be between 1 and 10 &#8486;/cm.</li>
		<li>Introduce the substrates in a piranha solution for 20 min in order to eliminate possible&#160;polymer residues.</li>
		<li>Clean with DI water, then with ethanol, and let them dry or use nitrogen flow. This step should be performed just after step 1.3.</li>
	</ol>
	</li>
	<li>Deposition of a solution containing pre-hydrolyzed tetraethyl orthosilicate (TEOS), Brij-58 sulfactant and SrCl2 6H2O.
	<ol>
		<li>In order to obtain a homogeneous silica film, set the dip-coater&#8217;s chamber under the conditions at relative humidity 40% and 25 &#176;C of temperature.</li>
		<li>Place a beaker with the size of around 5 cm x 1 cm x 8 cm underneath the SOI substrate hanging from the dip-coater arm and establish a dip coating sequence with the speed of 300 mm/min at the immersion and withdrawal. Set the immersion time (time at the final position) to zero.</li>
		<li>Fill the beaker with the solution prepared in step 1.3 and wait until the relative humidity temperature becomes stable, i.e., 40% and 25 &#176;C, respectively.</li>
		<li>Perform a single dip coating and wait until the film becomes homogeneous.</li>
		<li>Introduce the SOI substrate into a furnace at 450 &#176;C for 5 min for the consilidation of the gel film to obtaine a thickness of 200 nm.</li>
		<li>Repeat steps 3.2.3 and 3.2.4 two times more to produce a film with around 600 nm of thickness. To ensure the stability of the solution, a repeating process should be performed in 1 h.</li>
	</ol>
	</li>
</ol>
4. Surface micro/nanostructuration by soft imprint lithography
<ol>
	<li>Prepare the micro/nano structures on the film surface under the conditions of relative humidity 40% and 25 &#176;C of temperature.
	<ol>
		<li>Repeat step 3.2.3 to deposit a new film on SOI substrate.</li>
		<li>Place the SOI substrate after step 3.2.1 on a flat surface and put the PDMS mold prepared in step 2.2 on the SOI substrate while the sol-gel is evaporating.</li>
		<li>Put the SOI substrate with the PDMS mold in a furnace at 70 &#176;C for 1 min, and then at 140 &#176;C for 2 min in a second furnace. Then, leave it for cooling down.</li>
		<li>Remove the PDMS mold to obtain a micro/nanostructured gel film on the SOI substrate.</li>
		<li>Introduce the SOI substrate into a furnace at 450 &#176;C for 5 min to consolidate a micro/nanostructured gel film with 600 nm height.</li>
	</ol>
	</li>
</ol>
5. Gel film crystallization by thermal treatment
<ol>
	<li>Thermal treatment of the gel films on SOI (100).
	<ol>
		<li>Program the tubular furnace heating from room temperature to 1000 &#176;C.</li>
		<li>Introduce the sample placed in a ceramic boat into the furnace at 1000 &#176;C for 5 hours. Do not cover the tubular working tube during the whole thermal treatment in order to saturate the furnace with air. Finally, reach the room temperature by cooling the furnace without any programmed ramp.</li>
	</ol>
	</li>
</ol>
6. Designing of lithography mask layout
The mask used in this process is designed specifically for a device fabrication on the SOI substrate with epitaxial nanostructured quartz. All the fabrication processes are carried out on the quartz side. The mask was designed in a way that negative tone resist needs to be used in each step. The mask is organized in four different steps as explained below.
<ol>
	<li>Pattern the quartz to determine the shape of the cantilever and also 30 &#181;m x 30 &#181;m square shape contact area. For example, 40 &#181;m x 100 &#181;m size rectangular shape cantilever area out of 120 &#181;m x 160 &#181;m area is protected with negative resist and the rest is etched until silicon layer.</li>
	<li>Realize the top and bottom electrodes. Top electrode is patterned on the rectangular shaped cantilever area and the bottom electrode is patterned on the 2 &#181;m thick silicon layer on the 30 &#181;m x 30 &#181;m etched area. The width of the top contact is 4 &#181;m smaller than the patterned cantilever area and the size of the bottom contact is bigger than the 30 &#181;m x 30 &#181;m square shape etched area in step 1.</li>
	<li>Etch all the 2 &#181;m thick silicon layers in 120 &#181;m x 160 &#181;m U-shaped area around the rectangle-shaped cantilever. The etched area is again U-shaped but 4 &#181;m smaller from each side to protect the cantilever area from HF attack in the last step.</li>
	<li>Release the cantilever with BOE etching of SiO2. The protected cantilever area is 2 &#181;m bigger than the actual cantilever area. The most important part is to protect the surface and blanks of the cantilever.</li>
</ol>
7. Cleaning of the quartz samples for the cantilever microfabrication process with piranha solution
<ol>
	<li>Prepare a piranha solution by slowly adding 10 mL of hydrogen peroxide (H2O2) into 20 mL of sulfuric acid (H2SO4) at ambient temperature. This mixture creates a thermal reaction.
	<ol>
		<li>Put the samples inside this solution for 10 min in order to clean all the organic residues.</li>
		<li>Rinse the samples with DI water and dry them with nitrogen.</li>
	</ol>
	</li>
</ol>
8. Step 1: Patterning cantilever shape on the quartz thin film
<ol>
	<li>The first lithography process
	<ol>
		<li>Rinse the samples with acetone, IPA, and then blow dry&#160;nitrogen.</li>
		<li>Put the samples on the hot plate at 140&#176;C for 10 min of dehumidification.</li>
		<li>Spin AZ2070 negative photoresist at a speed of 4000 rpm for 30 s.</li>
		<li>Put the samples on the hot plate to softbake at 115 &#176;C for 60 s.</li>
		<li>Expose the sample with 37.5 mJ.cm-2 UV dose for 5 s.</li>
		<li>Put the sample on the hot plate for post exposure bake at 115 &#176;C for 60 s.</li>
		<li>Develop in MIF 726 developer for 100 s at ambient temperature, then rinse in DI water and blow dry&#160;nitrogen. The expected thickness is 5.5 &#956;m.</li>
		<li>Put the sample on the hotplate at 125 &#176;C for 10 min to hardbake the resist.</li>
	</ol>
	</li>
	<li>Reactive Ion Etching (RIE) of the quartz layer
	<ol>
		<li>Etch the quartz until silicon layer using RIE with a gas flow rate of 60 sccm CHF3, 20 sccm 02, and 10 sccm Ar at 100 W RF power.</li>
	</ol>
	</li>
	<li>Cleaning the resist residuals
	<ol>
		<li>Clean with plasma at a flow rate of 90 sccm 02 for 5 min.</li>
		<li>If the first cleaning step is not enough, leave the sample in remover PG at 80 &#176;C until all the resists are removed.</li>
		<li>Then, put the sample in a piranha solution (20 mL of sulfuric acid H2SO4 + 10 mL of hydrogen peroxide H2O2) for 10 min. Then, rinse in DI water and blow dry with nitrogen.</li>
	</ol>
	</li>
</ol>
9. Step 2: Realization of bottom and top electrode
<ol>
	<li>The second lithography process
	<ol>
		<li>Rinse the samples with acetone, IPA, and then blow dry&#160;nitrogen.</li>
		<li>Put the samples on the hot plate at 140 &#176;C for 10 min of dehumidification.</li>
		<li>Spin AZ2020 negative photoresist at a speed of 4000 rpm for 30 s.</li>
		<li>Put the sample on the hot plate to softbake at 115 &#176;C for 60 s.</li>
		<li>Expose the sample with 23.25 mJ.cm-2 UV dose for 3 s.</li>
		<li>Put the sample on the hot plate for post exposure bake at 115 &#176;C for 60 s.</li>
		<li>Develop in MIF 726 developer for 50 s at ambient temperature, then rinse in DI water and blow dry&#160;nitrogen. The expected thickness is 1.7 &#956;m.</li>
	</ol>
	</li>
	<li>Metal deposition for top and bottom electrodes.
	<ol>
		<li>Deposit 50 nm Chromium at a rate of 4 A/s and 120 nm Platinum at 2.5 A/s with electron beam evaporation at 10-6 mbar.</li>
	</ol>
	</li>
	<li>Metal lift-off
	<ol>
		<li>Leave the samples firstly in acetone and then in IPA until metal lift off is successful.</li>
		<li>Check the sample with an optical microscope and if necessary, leave the sample in remover PG at 80 &#176;C until all metals lift-off. Then, rinse in DI water and blow dry&#160;nitrogen.</li>
		<li>If step 9.3.2 is not enough, put the samples in an ultrasonic cleaner in acetone for 5 min. Repeat this operation as many times as necessary.</li>
		<li>Rinse the samples with acetone, IPA, and then blow dry with nitrogen.</li>
	</ol>
	</li>
</ol>
10. Step 3: Patterning the sample to etch Si(100) layer
<ol>
	<li>The third lithography process
	<ol>
		<li>Rinse the samples with acetone, IPA, and then blow dry&#160;nitrogen.</li>
		<li>Put the samples on the hot plate at 140 &#176;C for 10 min of dehumidification.</li>
		<li>Spin AZ2070 negative photoresist at a speed of 2000 rpm for 30 s.</li>
		<li>Put the sample on the hotplate for softbake at 115 &#176;C for 60 s.</li>
		<li>Expose the sample with 37.5 mJ.cm-2 UV dose for 5 s.</li>
		<li>Put the sample on the hotplate for post exposure bake at 115 &#176;C for 60 s.</li>
		<li>Develop in MIF 726 for 110 s at ambient temperature, then rinse in DI water and blow dry with nitrogen. The expected thickness is 5.9 &#956;m.</li>
		<li>Put the sample on the hot plate at 125 &#176;C for 10 min to hardbake the resist.</li>
	</ol>
	</li>
	<li>Reactive Ion Etching of the silicon layer
	<ol>
		<li>Etch the silicon layer until SiO2 layer using RIE with gas flow rate of 60 sccm CHF3, 20 sccm 02 and 10 sccm Ar at 100W RF power.</li>
	</ol>
	</li>
	<li>Cleaning the resist residuals
	<ol>
		<li>First clean with plasma at a flow rate of 90 sccm 02 for 5 min.</li>
		<li>Leave the sample in remover PG at 80 &#176;C until all resists are removed. Then, rinse in DI water and blow dry&#160;nitrogen.</li>
	</ol>
	</li>
</ol>
11. Step 4: Releasing cantilever by wet chemical etching of SiO2
<ol>
	<li>The fourth lithography process
	<ol>
		<li>Rinse the samples with acetone, IPA, and then blow dry&#160;nitrogen.</li>
		<li>Put the samples on the hot plate at 140 &#176;C for 10 min of dehumidification.</li>
		<li>Spin AZ2020 negative photoresist at a speed of 2000 rpm for 30 s.</li>
		<li>Put the sample on the hotplate for soft bake at 115 &#176;C for 60 s.</li>
		<li>Expose the sample with 37.5 mJ.cm-2 UV dose for 5 s.</li>
		<li>Put the sample on the hotplate for post exposure bake at 115 &#176;C for 60 s.</li>
		<li>Develop in MIF 726 for 65 s at ambient temperature. Rinse in DI water and then blow dry&#160;nitrogen. The expected thickness is 2.3 &#956;m.</li>
		<li>Put the sample on the hotplate at 125 &#176;C for 10 min to hardbake the resist.</li>
	</ol>
	</li>
	<li>Wet etching of SiO2 layer with buffered oxide etch (BOE)
	<ol>
		<li>Put BOE 7:1 solution in a polytetrafluoroethylene (PTFE) based container.</li>
		<li>Put the sample in this solution and leave it at ambient temperature until all SiO2 layers are etched under the cantilever. Then rinse in DI water and blow dry nitrogen.</li>
	</ol>
	</li>
	<li>Cleaning the resist residuals
	<ol>
		<li>Rinse the samples with acetone, IPA, and then blow dry&#160;nitrogen.</li>
		<li>If necessary, clean the resist residuals with plasma at a flow rate of 90 sccm O2 for 5 min.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Vila-Fungueiri&#241;o, J. M., 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=Integration+of+functional+complex+oxide+nanomaterials+on+silicon.">Integration of functional complex oxide nanomaterials on silicon.</a> Frontiers in Physics. 3, (2015).</li><li>Carretero-Genevrier, 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=Direct+monolithic+integration+of+vertical+single+crystalline+octahedral+molecular+sieve+nanowires+on+silicon.">Direct monolithic integration of vertical single crystalline octahedral molecular sieve nanowires on silicon.</a> Chemistry of Materials. 26 (2), 1019-1028 (2014).</li><li>Gomez, 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=Crystal+engineering+of+room-temperature+ferroelectricity+in+epitaxial+1D+hollandite+oxides+on+silicon.">Crystal engineering of room-temperature ferroelectricity in epitaxial 1D hollandite oxides on silicon.</a> arXiv:2007.03452 [cond-mat.mtrl-sci]. , (2020).</li><li>Tadigadapa, 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=Piezoelectric+MEMS+sensors:+state-of-the-art+and+perspectives.">Piezoelectric MEMS sensors: state-of-the-art and perspectives.</a> Measurement Science and Technology. 20 (9), 092001 (2009).</li><li>Yin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integration+of+epitaxial+piezoelectric+thin+films+on+silicon.">Integration of epitaxial piezoelectric thin films on silicon.</a> Ecole Centrale de Lyon, France. , (2013).</li><li>Isarakorn, 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=Epitaxial+piezoelectric+MEMS+on+silicon.">Epitaxial piezoelectric MEMS on silicon.</a> Journal of Micromechanics and Microengineering. 20 (5), 055008 (2010).</li><li>Craighead, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoelectromechanical+systems.">Nanoelectromechanical systems.</a> Science. 290 (5496), 1532-1535 (2000).</li><li>Warusawithana, M. 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=A+ferroelectric+oxide+made+directly+on+silicon.">A ferroelectric oxide made directly on silicon.</a> Science. 324 (5925), 367-370 (2009).</li><li>Galliou, 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=Quality+factor+measurements+of+various+types+of+quartz+crystal+resonators+operating+near+4+K.">Quality factor measurements of various types of quartz crystal resonators operating near 4 K.</a> IEEE Transactions on Ultrasonic, Ferroelectrics, and Frequency Control. 63 (7), (2015).</li><li>Danel, J. S., Delapierre, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quartz:+a+material+for+microdevices.">Quartz: a material for microdevices.</a> Journal of Micromechanics and Microengineering. 1 (4), 187 (1991).</li><li>Sohn, Y. 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=Mechanical+and+optical+nanodevices+in+single-crystal+quartz.">Mechanical and optical nanodevices in single-crystal quartz.</a> Applied Physics Letters. 111 (26), 263103 (2017).</li><li>Santybayeva, Z., 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=Fabrication+of+quartz+microcylinders+by+laser+interference+lithography+for+angular+optical+tweezers.">Fabrication of quartz microcylinders by laser interference lithography for angular optical tweezers.</a> Journal of Micro/Nanolithography, MEMS, and MOEMS. 15, 3 (2016).</li><li>Lu, 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=Enhanced+electro-optical+lithium+niobate+photonic+crystal+wire+waveguide+on+a+smart-cut+thin+film.">Enhanced electro-optical lithium niobate photonic crystal wire waveguide on a smart-cut thin film.</a> Optics Express. 20 (3), 2974-2981 (2012).</li><li>Carretero-Genevrier, 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=Soft-chemistry-based+routes+to+epitaxial+alpha-quartz+thin+films+with+tunable+textures.">Soft-chemistry-based routes to epitaxial alpha-quartz thin films with tunable textures.</a> Science. 340 (6134), 827-831 (2013).</li><li>Carretero-Genevrier, A., Gich, M. <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+macroporous+epitaxial+quartz+films+on+silicon+by+chemical+solution+deposition.">Preparation of macroporous epitaxial quartz films on silicon by chemical solution deposition.</a> Journal of Visualized Experiments: JoVE. (106), e53543 (2015).</li><li>Zhang, Q., 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+the+crystal+growth+of+quartz+on+silicon+for+patterning+epitaxial+piezoelectric+films.">Tailoring the crystal growth of quartz on silicon for patterning epitaxial piezoelectric films.</a> Nanoscale Advances. 1 (9), 3741-3752 (2019).</li><li>Zhang, Q., 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=Micro/nanostructure+engineering+of+epitaxial+piezoelectric+&#945;-quartz+thin+films+on+silicon.">Micro/nanostructure engineering of epitaxial piezoelectric &#945;-quartz thin films on silicon.</a> ACS Applied Materials &amp; Interfaces. 12 (4), 4732-4740 (2020).</li><li>Sansen, 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=Mapping+cell+membrane+organization+and+dynamics+using+soft+nanoimprint+lithography.">Mapping cell membrane organization and dynamics using soft nanoimprint lithography.</a> ACS Applied Materials &amp; Interfaces. 12 (26), 29000-29012 (2020).</li><li>Jolly, 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=Soft+chemistry+assisted+on-chip+integration+of+nanostructured+quartz-based+piezoelectric+microelectromechanical+system.">Soft chemistry assisted on-chip integration of nanostructured quartz-based piezoelectric microelectromechanical system.</a> arXiv:2007.07566 [physics.app-ph]. , (2020).</li></ol>

The authors have nothing to disclose.

The presented method is a combination of bottom-up and top-down approaches to produce nanostructured piezoelectric quartz micro-cantilevers on Si. Quartz/Si-MEMS technology offers major advantages over bulk quartz in terms of size, power consumption, and integration cost. Indeed, epitaxial quartz/Si MEMS are produced with CMOS-compatible processes. This could facilitate the future fabrication of single chip solutions for multifrequency devices while preserving miniaturization and cost-effective processes. Compared to the...

Oxide nanomaterials with piezoelectric properties are pivotal to design devices such as MEMS sensors or micro energy harvesters or storage1,2,3. As the advances in CMOS technology increase, the monolithic integration of high-quality epitaxial piezoelectric films and nanostructures into silicon becomes a subject of interest to expand new novel devices4. In addition, greater control of miniaturization of these devices is required to achieve high performances5,6. New sensor applications in electronic, biology, and medicine are enabled by the advances in micro and nanofabrication technologies7,8.
In particular, &#945;-quartz is widely used as a piezoelectric material and shows outstanding characteristics, which allow users to make fabrication for different applications. Although it has low electromechanical coupling factor, which limits its application area for energy harvesting, its chemical stability and high mechanical quality factor make it a good candidate for frequency control devices and sensor technologies9. However, these devices were micromachined from bulk single quartz crystals which have the desired characteristics for device fabrication10. The thickness of the quartz crystal should be configured in such a way that the highest resonance frequency can be obtained from the device, nowadays, the lowest achievable thickness is 10 &#956;m11. So far, some techniques to micropattern the bulk crystals such as Faraday cage angled-etching11, laser interference lithography12, and focused ion beam (FIB)13 were reported.
Recently, direct and bottom-up integration of epitaxial growth of (100) &#945;-quartz film into silicon substrate (100) was developed by chemical solution deposition (CSD)14,15. This approach opened a door to overcome the aforementioned challenges and also to develop piezoelectric-based devices for future sensor applications. Tailoring the structure of &#945;-quartz film on silicon substrate was achieved and it allowed to control the texture, density, and the thickness of the film16. The thickness of the &#945;-quartz film was extended from a few hundred nanometers to the micron range, which are 10 to 50 times thinner than those obtained by top-down technologies on bulk crystal. Optimizing the dip-coating deposition conditions, humidity and temperature was enabled to attain both continuous nanostructured crystalline quartz film and a perfect nanoimprinted pattern by a combination of a set of top-down lithography techniques17. Specifically, soft nanoimprint lithography (NIL) is a low-cost, large-scale fabrication and benchtop equipment-based process. Application of soft NIL, which combines top-down and bottom-up approaches, is a key to produce epitaxial quartz nanopillar arrays on silicon with a precise control of pillar diameters, height, and the interpillar distances. Furthermore, fabrication of silica nanopillar with controlled shape, diameter, and periodicity on borosilicate glass for a biological application was performed customizing soft NIL of epitaxial quartz thin film18.
Up to now, it has not been possible for on-chip integration of piezoelectric nanostructured &#945;-quartz MEMS. Here, we draw the detailed engineering route starting from material to device fabrication. We explain all the steps for material synthesis, soft NIL, and the microfabrication of the device to release a piezoelectric quartz cantilever on SOI substrate19 and discuss its response as a piezoelectric material with some characterization results.

<table>
	<tbody>
		<tr>
			<td>Acetone</td>
			<td>Honeywell Riedel de Ha&#235;n</td>
			<td>UN 1090</td>
			<td></td>
		</tr>
		<tr>
			<td>AZnLOF 2020 negative resist</td>
			<td>Microchemicals</td>
			<td>USAW176488-1BLO</td>
			<td></td>
		</tr>
		<tr>
			<td>AZnLOF 2070 negative resist</td>
			<td>Microchemicals</td>
			<td>USAW211327-1FK6</td>
			<td></td>
		</tr>
		<tr>
			<td>AZ 726 MIF developer</td>
			<td>Merck</td>
			<td>DEAA195539</td>
			<td></td>
		</tr>
		<tr>
			<td>BOE (7:1)</td>
			<td>Technic</td>
			<td>AF 87.5-12.5</td>
			<td></td>
		</tr>
		<tr>
			<td>Brij-58</td>
			<td>Sigma</td>
			<td>9004-95-9</td>
			<td></td>
		</tr>
		<tr>
			<td>Chromium</td>
			<td>Neyco</td>
			<td>FCRID1T00004N-F53-062317/FC79271</td>
			<td></td>
		</tr>
		<tr>
			<td>Dip Coater ND-R 11/2 F</td>
			<td>Nadetec</td>
			<td>ND-R 11/2 F</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen peroxide solution 30%</td>
			<td>Carlo Erka Reagents DasitGroup</td>
			<td>UN 2014</td>
			<td></td>
		</tr>
		<tr>
			<td>H2SO4</td>
			<td>Honeywell Fluka</td>
			<td>UN 1830</td>
			<td></td>
		</tr>
		<tr>
			<td>Isopropyl alcohol</td>
			<td>Honeywell Riedel de Ha&#235;n</td>
			<td>UN 1219</td>
			<td></td>
		</tr>
		<tr>
			<td>Mask aligner</td>
			<td>EV Group</td>
			<td>EVG620</td>
			<td></td>
		</tr>
		<tr>
			<td>PG remover</td>
			<td>MicroChem</td>
			<td>18111026</td>
			<td></td>
		</tr>
		<tr>
			<td>Platinum</td>
			<td>Neyco</td>
			<td>INO272308/F14508</td>
			<td></td>
		</tr>
		<tr>
			<td>PTFE based container</td>
			<td>Teflon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reactive ion etching (RIE)</td>
			<td>Corial</td>
			<td>ICP Corial 200 IL</td>
			<td></td>
		</tr>
		<tr>
			<td>SEMFEG</td>
			<td>Hitachi</td>
			<td>Su-70</td>
			<td></td>
		</tr>
		<tr>
			<td>SOI substrate</td>
			<td>University Wafer</td>
			<td>ID :3213</td>
			<td></td>
		</tr>
		<tr>
			<td>Strontium chloride hexahydrate</td>
			<td>Sigma-Aldrich</td>
			<td>10025-70-4</td>
			<td></td>
		</tr>
		<tr>
			<td>SYLGARD TM 184 Silicone Elastomer Kit</td>
			<td>Dow</td>
			<td>.000000840559</td>
			<td></td>
		</tr>
		<tr>
			<td>SYLGARD TM 184 Silicone Elastomer Curring Agent</td>
			<td>Dow</td>
			<td>.000000840559</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetraethyl orthosilicate</td>
			<td>Aldrich</td>
			<td>78-10-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Tubular Furnace</td>
			<td>Carbolite</td>
			<td>PTF 14/75/450</td>
			<td></td>
		</tr>
		<tr>
			<td>Vibrometer</td>
			<td>Polytec</td>
			<td>OFV-500D</td>
			<td></td>
		</tr>
		<tr>
			<td>2D XRD</td>
			<td>Bruker</td>
			<td>D8 Discover</td>
			<td>Equipped with a Eiger2 R 500 K 2D detector</td>
		</tr>
	</tbody>
</table>

epitaxial nanostructured &alpha;-quartz films on silicon: from the material to new devices

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all the steps in the process starting from the material to the device fabrication. The epitaxial growth of &#945;-quartz film on SOI (100) substrate starts with the preparation of a strontium doped silica sol-gel and continues with the deposition of this gel into the SOI substrate in a thin film form using the dip-coating technique under atmospheric conditions at room temperature. Before crystallization of the gel film, nanostructuration is performed onto the film surface by nanoimprint lithography (NIL). Epitaxial film growth is reached at 1000 &#176;C, inducing a perfect crystallization of the patterned gel film. Fabrication of quartz crystal cantilever devices is a four-step process based on microfabrication techniques. The process starts with shaping the quartz surface, and then metal deposition for electrodes follows it. After removing the silicone, the cantilever is released from SOI substrate eliminating SiO2 between silicon and quartz. The device performance is analyzed by non-contact laser vibrometer (LDV) and atomic force microscopy (AFM). Among the different cantilever&#8217;s dimensions included in the fabricated chip, the nanostructured cantilever analyzed in this work exhibited a dimension of 40 &#181;m large and 100 &#181;m long and was fabricated with a 600 nm thick patterned quartz layer (nanopillar diameter and separation distance of 400 nm and 1 &#181;m, respectively) epitaxially grown on a 2 &#181;m thick Si device layer. The&#160;measured&#160;resonance frequency was&#160;267 kHz and the estimated quality factor, Q, of the whole mechanical structure was Q ~ 398 under low vacuum conditions. We observed the voltage-dependent linear displacement of cantilever with both techniques (i.e., AFM contact measurement and LDV). Therefore, proving that these devices can be activated through the indirect piezoelectric effect.

The progress of the material synthesis and device fabrication (see Figure 1) was depicted schematically by monitoring different steps with real images. After the microfabrication processes, we observed the aspect of the nanostructured cantilevers using the field emission Scanning Electron Microscopy (FEG-SEM) images (Figure 2a-c). 2D Micro X-ray diffraction controlled the crystallinity of the different stacking layers of the cantilever (<strong ...

Watch this Scientific Journal Video about Epitaxial Nanostructured ÃŽÂ±-Quartz Films on Silicon: From the Material to New Devices at JoVE.com

Epitaxial Nanostructured &#945;-Quartz Films on Silicon: From the Material to New Devices

This work presents a detailed protocol for the microfabrication of nanostructured &#945;-quartz cantilever on a Silicon-On-Insulator(SOI) technology substrate starting from the epitaxial growth of quartz film with the dip coating method and then nanostructuration of the thin film via nanoimprint lithography.

Epitaxial Nanostructured &alpha;-Quartz Films on Silicon: From the Material to New Devices

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all ...

epitaxial-nanostructured-quartz-films-on-silicon-from-material-to-new

Research

JoVE Journal

Engineering

5.3K Views.  Université de Montpellier. This work presents a detailed protocol for the microfabrication of nanostructured α-quartz cantilever on a Silicon-On-Insulator(SOI) technology substrate starting from the epitaxial growth of quartz film with the dip coating method and then nanostructuration of the thin film via nanoimprint lithography.

Video: Epitaxial Nanostructured α-Quartz Films on Silicon: From the Material to New Devices

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

Measuring Spatially- and Directionally-varying Light Scattering from Biological Material

Light interacts with an organism's integument on a variety of spatial scales. For example in an iridescent bird: nano-scale structures produce color; the milli-scale structure of barbs and barbules largely determines the directional pattern of reflected light; and through the macro-scale spatial structure of overlapping, curved feathers, these directional effects create the visual texture. Milli-scale and macro-scale effects determine where on the organism's body, and from what viewpoints and under what illumination, the iridescent colors are seen. Thus, the highly directional flash of brilliant color from the iridescent throat of a hummingbird is inadequately explained by its nano-scale structure alone and questions remain. From a given observation point, which milli-scale elements of the feather are oriented to reflect strongly? Do some species produce broader "windows" for observation of iridescence than others? These and similar questions may be asked about any organisms that have evolved a particular surface appearance for signaling, camouflage, or other reasons.
In order to study the directional patterns of light scattering from feathers, and their relationship to the bird's milli-scale morphology, we developed a protocol for measuring light scattered from biological materials using many high-resolution photographs taken with varying illumination and viewing directions. Since we measure scattered light as a function of direction, we can observe the characteristic features in the directional distribution of light scattered from that particular feather, and because barbs and barbules are resolved in our images, we can clearly attribute the directional features to these different milli-scale structures. Keeping the specimen intact preserves the gross-scale scattering behavior seen in nature. The method described here presents a generalized protocol for analyzing spatially- and directionally-varying light scattering from complex biological materials at multiple structural scales.

We present a non-destructive method for sampling spatial variation in the direction of light scattered from structurally complex materials. By keeping the material intact, we preserve gross-scale scattering behavior, while concurrently capturing fine-scale directional contributions with high-resolution imaging. Results are visualized in software at biologically-relevant positions and scales.

Light interacts with an organism's integument on a variety of spatial scales. For example in an iridescent bird: nano-scale structures produce color; the ...

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra shallow and sharp doping profiles at the nanometer scale. In MLCD process the dopant source is a monolayer containing dopant atoms.
In this article a detailed procedure for surface doping of silicon substrate as well as silicon nanowires is demonstrated. Phosphorus dopant source was formed using tetraethyl methylenediphosphonate monolayer on a silicon substrate. This monolayer containing substrate was brought to contact with a pristine intrinsic silicon target substrate and annealed while in contact. Sheet resistance of the target substrate was measured using 4 point probe. Intrinsic silicon nanowires were synthesized by chemical vapor deposition (CVD) process using a vapor-liquid-solid (VLS) mechanism; gold nanoparticles were used as catalyst for nanowire growth. The nanowires were suspended in ethanol by mild sonication. This suspension was used to dropcast the nanowires on silicon substrate with a silicon nitride dielectric top layer. These nanowires were doped with phosphorus in similar manner as used for the intrinsic silicon wafer. Standard photolithography process was used to fabricate metal electrodes for the formation of nanowire based field effect transistor (NW-FET). The electrical properties of a representative nanowire device were measured by a semiconductor device analyzer and a probe station.

A detailed procedure for surface doping of Silicon interfaces is provided. The ultra-shallow surface doping is demonstrated by using phosphorus containing monolayers and rapid annealing process. The method can be used for doping of macroscopic area surfaces as well as nanostructures.

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra ...

Fabrication of Uniform Nanoscale Cavities via Silicon Direct Wafer Bonding

Measurements of the heat capacity and superfluid fraction of confined 4He have been performed near the lambda transition using lithographically patterned and bonded silicon wafers. Unlike confinements in porous materials often used for these types of experiments3, bonded wafers provide predesigned uniform spaces for confinement. The geometry of each cell is well known, which removes a large source of ambiguity in the interpretation of data.
Exceptionally flat, 5 cm diameter, 375 &#181;m thick Si wafers with about 1 &#181;m variation over the entire wafer can be obtained commercially (from Semiconductor Processing Company, for example). Thermal oxide is grown on the wafers to define the confinement dimension in the z-direction. A pattern is then etched in the oxide using lithographic techniques so as to create a desired enclosure upon bonding. A hole is drilled in one of the wafers (the top) to allow for the introduction of the liquid to be measured. The wafers are cleaned2 in RCA solutions and then put in a microclean chamber where they are rinsed with deionized water4. The wafers are bonded at RT and then annealed at ~1,100 &#176;C. This forms a strong and permanent bond. This process can be used to make uniform enclosures for measuring thermal and hydrodynamic properties of confined liquids from the nanometer to the micrometer scale.

A method for permanently bonding two silicon wafers so as to realize a uniform enclosure is described. This includes wafer preparation, cleaning, RT bonding, and annealing processes. The resulting bonded wafers (cells) have uniformity of enclosure ~1%1,2. The resulting geometry allows for measurements of confined liquids and gasses.

Measurements of the heat capacity and superfluid fraction of confined 4He have been performed near the lambda transition using lithographically patterned ...

Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by quantum mechanical effects such as tunneling through single dopants, scattering via interface defects, and discrete trap charge states. However, progress in silicon technology has shown that these phenomena can be harnessed and exploited for a new class of quantum-based electronics. Among others, multi-layer-gated silicon metal-oxide-semiconductor (MOS) technology can be used to control single charge or spin confined in electrostatically-defined quantum dots (QD). These QD-based devices are an excellent platform for quantum computing applications and, recently, it has been demonstrated that they can also be used as single-electron pumps, which are accurate sources of quantized current for metrological purposes. Here, we discuss in detail the fabrication protocol for silicon MOS QDs which is relevant to both quantum computing and quantum metrology applications. Moreover, we describe characterization methods to test the integrity of the devices after fabrication. Finally, we give a brief description of the measurement set-up used for charge pumping experiments and show representative results of electric current quantization.

The fabrication process and experimental characterization techniques relevant to single-electron pumps based on silicon metal-oxide-semiconductor quantum dots are discussed.

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by ...

In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films

Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs within the interlayer space of semiconducting layered titania nanosheet (TNS) films was investigated here. Two types of intermediate films (i.e., TNS films containing methyl viologen (TNS/MV2+) and 2-ammoniumethanethiol (TNS/2-AET+)) were prepared. The two intermediate films were soaked in an aqueous tetrachloroauric(III) acid (HAuCl4) solution, whereby considerable amounts of Au(III) species were accommodated within the interlayer spaces of the TNS films. The two types of obtained films were then soaked in an aqueous sodium tetrahydroborate (NaBH4) solution, whereupon the color of the films immediately changed from colorless to purple, suggesting the formation of AuNPs within the TNS interlayer. When only TNS/MV2+ was used as the intermediate film, the color of the film gradually changed from metallic purple to dusty purple within 30 min, suggesting that aggregation of AuNPs had occurred. In contrast, this color change was suppressed by using the TNS/2-AET+ intermediate film, and the AuNPs were stabilized for over 4 months, as evidenced by the characteristic extinction (absorption and scattering) band from the AuNPs.

In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films

Here, we present a protocol for the in situ synthesis of gold nanoparticles (AuNPs) within the interlayer space of layered titanate films without the aggregation of AuNPs. No spectral change was observed even after 4 months. The synthesized material has expected applications in catalysis, photo-catalysis, and the development of cost-effective plasmonic devices.

Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs ...

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360&#176; rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.

Scanning Light Scattering Profiler SLPS Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

This protocol describes the scanning light scattering profiler (SLSP) that enables the full-angle quantitative evaluation of forward and backward scattering of light from intraocular lenses (IOLs) using goniophotometer principles.

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light ...

High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as aqueous solutions and biomaterials, with fast acquisition times. Here, we discuss the assembly and operation of a Brillouin spectrometer that uses stimulated Brillouin scattering (SBS) to measure stimulated Brillouin gain (SBG) spectra of water and lipid emulsion-based tissue-like samples in transmission mode with &lt;10 MHz spectral-resolution and &lt;35 MHz Brillouin-shift measurement precision at &lt;100 ms. The spectrometer consists of two nearly counter-propagating continuous-wave (CW) narrow-linewidth lasers at 780 nm whose frequency detuning is scanned through the material Brillouin shift. By using an ultra-narrowband hot rubidium-85 vapor notch filter and a phase-sensitive detector, the signal-to-noise-ratio of the SBG signal is significantly enhanced compared to that obtained with existing CW-SBS spectrometers. This improvement enables measurement of SBG spectra with up to 100-fold faster acquisition times, thereby facilitating high spectral-resolution and high-precision Brillouin analysis of soft materials at high speed.

We describe the construction of a rapid continuous-wave-stimulated-Brillouin-scattering (CW-SBS) spectrometer. The spectrometer employs single-frequency diode-lasers and an atomic vapor notch-filter to acquire transmission spectra of turbid/non-turbid samples with high spectral-resolution at speeds up to 100-fold faster than those of existing CW-SBS spectrometers. This improvement enables high-speed Brillouin material analysis.

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as ...

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 ...

Hybrid Printing for the Fabrication of Smart Sensors

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, three substrates (acrylate, ceramics, and copper) are prepared. To determine the resulting material properties of these substrates, profilometer, contact angle, scanning electron microscope (SEM), and focused ion beam (FIB) measurements are done. The achievable printing resolution and suitable drop volume for each substrate are, then, found through the drop size tests. Then, layers of insulating and conductive ink are inkjet printed alternately to fabricate the target sensor structures. After each printing step, the respective layers are individually treated by photonic curing. The parameters used for the curing of each layer are adapted depending on the printed ink, as well as on the surface properties of the respective substrate. To confirm the resulting conductivity and to determine the quality of the printed surface, four-point probe and profilometer measurements are done. Finally, a measurement set-up and results achieved by such an all-printed sensor system are shown to demonstrate the achievable quality.

Here we present a protocol for the fabrication of inkjet-printed multilayer sensor structures on additively manufactured substrates and foil.

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, ...