Name: fabrication of 3d carbon microelectromechanical systems (c-mems)
Uploaded: 2017-06-17T13:00:00
Description: Watch this Scientific Journal Video about Fabrication of 3D Carbon Microelectromechanical Systems C-MEMS at JoVE.com

This work was supported by Technologico de Monterrey and the University of California at Irvine.

1. 3D Human Hair-derived Carbon Structure Fabrication
NOTE: Use personal protective equipment. Follow laboratory instructions to use the instruments and to work inside the laboratory.
<ol>
	<li>Prepare collected human hair by washing it with DI water and drying it with N2 gas.</li>
	<li>Arrange the hairs as desired, such as in parallel strands, cross over, with two hairs wound together, etc.</li>
	<li>Attach the hairs to a silicon substrate using SU8 or keep them directly...

<ol>
	<li>Wang, C., Jia, G., Taherabadi, L. H., Madou, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+method+for+the+fabrication+of+high-aspect+ratio+C-MEMS+structures.">A novel method for the fabrication of high-aspect ratio C-MEMS structures.</a> J Microelectromech Syst. 14 (2), 348-358 (2005).</li><li>Jong, K. P. D., Geus, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+nano&#64257;bers:+catalytic+synthesis+and+applications.">Carbon nano&#64257;bers: catalytic synthesis and applications.</a> Catal Rev Sci Eng. 42, 481-510 (2000).</li><li>Elrouby, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemical+applications+of+carbon+nanotube.">Electrochemical applications of carbon nanotube.</a> J Nano Adv Mat. 1 (1), 23-38 (2013).</li><li>Baughman, R. H., Zakhidov, A. A., Heer, W. A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+nanotubes-the+route+toward+applications.">Carbon nanotubes-the route toward applications.</a> Science. 297, 787-792 (2002).</li><li>Kumar, R., Singh, R. K., Singh, D. 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(1-3), 184-190 (2006).</li><li>Sharma, S., Kalita, G., Hirano, R., Hayashi, Y., Tanemura, M. <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+gas+composition+on+the+formation+of+graphene+domain+synthesized+from+camphor.">Influence of gas composition on the formation of graphene domain synthesized from camphor.</a> Mater Lett. 93, 258-262 (2013).</li><li>Ghosh, P., Afre, R. A., Soga, T., Jimbo, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+of+producing+single-walled+carbon+nanotubes+from+a+natural+precursor:+eucalyptus+oil.">A simple method of producing single-walled carbon nanotubes from a natural precursor: eucalyptus oil.</a> Mater Lett. 61 (17), 3768-3770 (2007).</li><li>Kumar, R., Tiwari, R., Srivastava, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scalable+synthesis+of+aligned+carbon+nanotubes+bundles+using+green+natural+precursor:+neem+oil.">Scalable synthesis of aligned carbon nanotubes bundles using green natural precursor: neem oil.</a> Nanoscale Res Lett. 6 (1), 92-97 (2011).</li><li>Liang, Y., Wu, D., Fu, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+microfibers+with+hierarchical+porous+structure+from+electrospun+fiber-like+natural+biopolymer.">Carbon microfibers with hierarchical porous structure from electrospun fiber-like natural biopolymer.</a> Sci Rep. 3, 1-5 (2013).</li><li>Gupta, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+hair+"waste"+and+its+utilization:+gaps+and+possibilities.">Human hair "waste" and its utilization: gaps and possibilities.</a> J Waste Manag. 2014, 1-17 (2014).</li><li>Qian, W., Sun, F., Xu, Y., Qiu, L., Liu, C., Wang, S., Yan, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+hair-derived+carbon+flakes+for+electrochemical+supercapacitors.">Human hair-derived carbon flakes for electrochemical supercapacitors.</a> Energy Environ Sci. 7, 379-386 (2014).</li><li>Pramanick, B., Cadenas, L. B., Kim, D. M., Lee, W., Shim, Y. B., Martinez-Chapa, S. O., Madou, M. J., Hwang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+hair-derived+hollow+carbon+microfibers+for+electrochemical+sensing.">Human hair-derived hollow carbon microfibers for electrochemical sensing.</a> Carbon. 107, 872-877 (2016).</li><li>Miura, N., Numaguchi, T., Yamada, A., Konagai, M., Shirakashi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Room+temperature+operation+of+amorphous+carbon-based+single-electron+transistors+fabricated+by+beam-induced+deposition+techniques.">Room temperature operation of amorphous carbon-based single-electron transistors fabricated by beam-induced deposition techniques.</a> Jpn J Appl Phys. 37 (2), L423-L425 (1998).</li><li>Irie, M., Endo, S., Wang, C. L., Ito, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+properties+of+lateral+p-i-p+structures+using+single+crystalline+CVD+diamond+layers+for+high+electric+&#64257;eld+applications.">Fabrication and properties of lateral p-i-p structures using single crystalline CVD diamond layers for high electric &#64257;eld applications.</a> Diamond Rel Mater. 12, 1563-1568 (2003).</li><li>Tay, B. K., Sheeja, D., Yu, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+stress+reduction+of+tetrahedral+amorphous+carbon+&#64257;lms+for+moving+mechanical+assemblies.">On stress reduction of tetrahedral amorphous carbon &#64257;lms for moving mechanical assemblies.</a> Diamond Rel Mater. 12 (2), 185-194 (2003).</li><li>Kamath, R. R., Madou, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+carbon+interdigitated+electrode+arrays+for+redox-amplification.">Three-dimensional carbon interdigitated electrode arrays for redox-amplification.</a> Anal Chem. 86 (6), 2963-2971 (2014).</li><li>Sharma, S., Khalajhedayati, A., Rupert, T. J., Madou, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SU8+derived+glassy+carbon+for+lithium+ion+batteries.">SU8 derived glassy carbon for lithium ion batteries.</a> ECS Trans. 61 (7), 75-84 (2014).</li><li>Kim, D., Pramanick, B., Salazar, A., Tcho, I. -. W., Madou, M. J., Jung, E. S., Choi, Y. -. K., Hwang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+carbon+electrode+based+triboelectric+nanogenerator.">3D carbon electrode based triboelectric nanogenerator.</a> Adv Mater Technol. 1 (8), 1-7 (2016).</li><li>Duarte, R. M., Gorkin, R. A., Samra, K. B., Madou, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+integration+of+3D+carbon-electrode+dielectrophoresis+on+a+CD-like+centrifugal+microfluidic+platform.">The integration of 3D carbon-electrode dielectrophoresis on a CD-like centrifugal microfluidic platform.</a> Lab Chip. 10 (8), 1030-1043 (2010).</li><li>Mund, K., Richter, G., Weidlich, E., Fahlstrom, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemical+properties+of+platinum,+glassy+carbon,+and+pyrographite+as+stimulating+electrodes.">Electrochemical properties of platinum, glassy carbon, and pyrographite as stimulating electrodes.</a> Pacing Clin Electrophysiol. 9 (6), 1225-1229 (1986).</li><li>Xua, H., Malladi, K., Wang, C., Kulinsky, L., Song, M., Madou, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+post-microarrays+for+glucose+sensors.">Carbon post-microarrays for glucose sensors.</a> Biosens Bioelectron. 23 (11), 1637-1644 (2008).</li><li>Sharma, S., Madou, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro+and+nano+patterning+of+carbon+electrodes+for+bioMEMS.">Micro and nano patterning of carbon electrodes for bioMEMS.</a> Bioinspir Biomim Nanobiomat. 1, 252-265 (2012).</li><li>Pramanick, B., Martinez-Chapa, S. O., Madou, M. <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+biocompatible+hollow+microneedles+using+the+C-MEMS+process+for+transdermal+drug+delivery.">Fabrication of biocompatible hollow microneedles using the C-MEMS process for transdermal drug delivery.</a> ECS Trans. 72 (1), 45-50 (2016).</li></ol>

In this paper the methods for manufacturing a variety of carbon microstructures based on the pyrolysis of natural precursor materials or photo-patterned polymer structures were reported. The carbon materials resulting from both the traditional and non-conventional C-MEMS/C-NEMS processes are typically found to be glassy carbons. Glassy carbon is a widely used electrode material for electrochemistry and also for high-temperature applications. The microstructure of glassy carbon is composed of both crystalline and amorphou...

Carbon has many allotropes and, depending on the particular application, one of the following allotropes can be chosen: carbon nanotubes (CNTs), graphite, diamond, amorphous carbon, lonsdaleite, buckminsterfullerene (C60), fullerite (C540), fullerene (C70), and glassy carbon1,2,3,4. Glassy carbon is one of the most widely used allotropes because of its physical properties, including high isotropy. It also has the following properties: good electrical conductivity, low thermal expansion coefficient, and gas impermeability.
There has been a continuous search for carbon-rich precursor materials to obtain carbon structures. These precursors can be manmade materials or natural products that are available in particular shapes, and even include waste products. A wide variety of micro/nanostructures are formed via biological or environmental processes in nature, resulting in unique features that are extremely difficult to create using conventional manufacturing tools. As patterning took place naturally in this case, the synthesis of nanomaterials using natural and waste hydrocarbon precursors could be carried out using an easy, one-step process of thermal decomposition in an inert or vacuum atmosphere, called pyrolysis5. High-quality graphene, single-walled CNTs, multi-walled CNTs, and carbon dots have been produced by thermal decomposition or the pyrolysis of plant-derived precursors and wastes, including seeds, fibers, and oils, such as turpentine oil, sesame oil, neem oil (Azadirachta indica), eucalyptus oil, palm oil, and jatropha oil. Also, camphor products, tea-tree extracts, waste foods, insects, agro wastes, and food products have been utilized6,7,8,9 Recently, researchers have even used silk cocoons as a precursor material to prepare porous carbon microfibers10. Human hair, usually considered a waste material, was recently used by this team. It is made up of approximately 91% polypeptides, which contain more than 50% carbon; the rest are elements such as oxygen, hydrogen, nitrogen, and sulphur11. Hair also comes with several interesting properties, such as very slow degradation, high tensile strength, high thermal insulation, and high elastic recovery. Recently, it has been used to prepare carbon flakes employed in supercapacitors12 and to create hollow carbon microfibers for electrochemical sensing13.
The machining of a bulk carbon material to fabricate three-dimensional (3D) structures is a difficult task, as the material is very brittle. Focused ion beam14,15 or reactive ion etching16 may be useful in this context, but they are expensive and time-consuming processes. Carbon microelectromechanical system (C-MEMS) technology, which is based on the pyrolysis of patterned polymeric structures, represents a versatile alternative. In the past two decades, C-MEMS and carbon nanoelectromechanical systems (C-NEMS) have received much attention because of the simple and inexpensive fabrication steps involved. The conventional C-MEMS fabrication process is carried out in two steps: (i) patterning a polymer precursor (e.g., a photoresist) with photolithography and (ii) pyrolysis of the patterned structures. Ultraviolet (UV)-curable polymer precursors, such as SU8 photoresists, are often used to pattern structures based on photolithography. In general, the photolithography process includes steps for spin coating, soft bake, UV exposure, post bake, and development. In the case of C-MEMS; silicon; silicon dioxide; silicon nitride; quartz; and, more recently, sapphire have been used as substrates. The photo-patterned polymer structures are carbonized at a high temperature (800-1,100 &#176;C) in an oxygen-free environment. At those elevated temperatures in a vacuum or inert atmosphere, all of the non-carbon elements are removed, leaving only carbon. This technique allows for the attainment of high-quality, glassy carbon structures, which are very useful for many applications, including electrochemical sensing17, energy storage18, triboelectric nanogeneration19, and electrokinetic particle manipulation20. Also, the fabrication of 3D microstructures with high aspect ratios using C-MEMS has become relatively easy and has led to a wide variety of carbon electrodes applications18,21,22,23, often replacing noble metal electrodes.
In this work, the recent development of a simple and cost-effective way to fabricate hollow carbon microfibers from human hair using non-conventional C-MEMS technology13 is introduced. The conventional SU8 polymer-based C-MEMS process is also described here. Specifically, the fabrication procedure for high-aspect ratio solids and hollow SU8 structures is described24.

<table border="0" cellpadding="0" cellspacing="0" width="690">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">SU8-2100</td>
			<td style="width:141px;">Microchem</td>
			<td style="width:167px;">Product number-Y1110750500L</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Spinner</td>
			<td style="width:141px;">Laurell Technologies Corporation</td>
			<td style="width:167px;">Model-WS650HZB-23NPP/UD3</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Hotplate</td>
			<td style="width:141px;">Torrey Pines Scientific</td>
			<td style="width:167px;">HS61</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">UV-exposer</td>
			<td style="width:141px;">Mercury Lamp, SYLVANIA</td>
			<td style="width:167px;">H44GS-100M, P/N-34-0054-01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Photomask</td>
			<td style="width:141px;">CAD/Art</td>
			<td style="width:167px;"></td>
			<td>No number</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Developer&#160;</td>
			<td style="width:141px;">Microchem</td>
			<td style="width:167px;">Y020100 4000L&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DI water system</td>
			<td style="width:141px;">Milli Q</td>
			<td style="width:167px;">ZOOQOVOTO</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">IPA</td>
			<td style="width:141px;">CTR Sientific</td>
			<td style="width:167px;">CTR 01244</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">N2 gas</td>
			<td style="width:141px;">AOC Mexico</td>
			<td style="width:167px;"></td>
			<td>No number</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Furnace</td>
			<td style="width:141px;">PEO 601, ATV Technologie GMBH</td>
			<td style="width:167px;">Model-PEO 601, Serial no.-195</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Si/SiO2</td>
			<td style="width:141px;">Noel Technologies</td>
			<td style="width:167px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

fabrication of 3d carbon microelectromechanical systems (c-mems)

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long and hollow glassy carbon microfibers derived from human hairs is introduced. The long and hollow carbon structures were made by the pyrolysis of human hair at 900 &#176;C in a N2 atmosphere. The morphology and chemical composition of natural and pyrolyzed human hairs were investigated using scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDX), respectively, to estimate the physical and chemical changes due to pyrolysis. Raman spectroscopy was used to confirm the glassy nature of the carbon microstructures. Pyrolyzed hair carbon was introduced to modify screen-printed carbon electrodes ; the modified electrodes were then applied to the electrochemical sensing of dopamine and ascorbic acid. Sensing performance of the modified sensors was improved as compared to the unmodified sensors. To obtain the desired carbon structure design, carbon micro-/nanoelectromechanical system (C-MEMS/C-NEMS) technology was developed. The most common C-MEMS/C-NEMS fabrication process consists of two steps: (i) the patterning of a carbon-rich base material, such as a photosensitive polymer, using photolithography; and (ii) carbonization through the pyrolysis of the patterned polymer in an oxygen-free environment. The C-MEMS/NEMS process has been widely used to develop microelectronic devices for various applications, including in micro-batteries, supercapacitors, glucose sensors, gas sensors, fuel cells, and triboelectric nanogenerators. Here, recent developments of a high-aspect ratio solid and hollow carbon microstructures with SU8 photoresists are discussed. The structural shrinkage during pyrolysis was investigated using confocal microscopy and SEM. Raman spectroscopy was used to confirm the crystallinity of the structure, and the atomic percentage of the elements present in the material before and after pyrolysis was measured using EDX.

A schematic of the fabrication process for human hair-derived hollow carbon microfibers is shown in Figure 1. The carbonized human hair was characterized using SEM to estimate the shrinkage. The hair diameter shrank from 82.88 &#177; 0.003 &#181;m to 31.42 &#177; 0.003 &#181;m due to the pyrolysis. Scanning electron microscopic (SEM) images of various patterns made using hair-derived carbon microfibers are shown in Figure 2. The ...

Watch this Scientific Journal Video about Fabrication of 3D Carbon Microelectromechanical Systems C-MEMS at JoVE.com

Fabrication of 3D Carbon Microelectromechanical Systems C-MEMS

Long and hollow glassy carbon microfibers were fabricated based on the pyrolysis of a natural product, human hair. The two fabrication steps of carbon microelectromechanical and carbon nanoelectromechanical systems, or C-MEMS and C-NEMS, are: (i) photolithography of a carbon-rich polymer precursor and (ii) pyrolysis of the patterned polymer precursor.

Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS)

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long ...

The overall goal of this procedure is to fabricate 3D carbon structures using conventional and nonconventional carbon microelectromechanical system processes with carbon sources of SU-8 polymer and human hair, respectively. 20 years ago, we actually started a complete new process where we are replacing silicon as the major material for making MEMS devices, microelectromechanical systems. Our idea is that carbon is a better material than silicon for making these three-dimensional shapes.Specifically, we take a polymer precursor, pattern it, and then convert it to carbon at high temperature, around 900 to 1, 000 degrees C, in an inert atmosphere. What happens in that process is the shape is preserved, but it shrinks. In order words, you have isometric shrinkage, and you end up with any 3D carbon shape you might imagine.That is called carbon MEMS. It is much less expensive because all I do is take a carbon precursor, a polymer, and pattern it in three dimension and then convert it to carbon. Carbon comes in many allotropes, from diamond to graphite to glassy carbon.Depending on how I pretreat the polymer's chains, I can actually end up with a 3D carbon structure that's more graphitic or more diamond-like or glassy carbon-like. Today, the process of carbon MEMS will be demonstrated for you by my graduate student, Esham Shomloo. To begin the polymer structure fabrication procedure, first set a hotplate to 95 degrees Celsius.Turn on a spin coater and the connected vacuum pump. Program a two-step spin coating sequence with a first step of 10 seconds at 500 rpm and a second step of 30 seconds at 1, 000 rpm, both with a ramp rate of 100 rpm per second. Place a silicon wafer or other substrate on the vacuum holder of the spin coater.Start the vacuum to fix the substrate to the holder. Apply sufficient epoxy resin-based negative photoresist to cover the surface of the substrate. Run the two-step spin coating sequence to achieve a final photoresist thickness of one to 250 micron.Release the substrate from the holder. Using tweezers, carefully transfer the substrate to the 95 degrees Celsius hotplate without disturbing the thin film. Bake the substrate at 95 degrees Celsius for one to 40 minutes, depending on the thickness of the photoresist.During the soft bake, turn on the photolithography UV system and set the exposure time to 12 seconds. Once the soft bake has completed, transfer the substrate to the UV system. Clamp the patterned mask with a vacuum mask holder.Place the mask holder with the mask on the UV exposure system. Put the photoresist-coated substrate on the stage of the UV exposure system. Cover the substrate with the patterned mask, and gently press the mask against the substrate.Expose the substrate to UV light for the set duration, and then separate the mask from the substrate, Perform a post-exposure bake at 95 degrees Celsius for one to 15 minutes, depending on the thickness of the photoresist. Immerse the substrate in the appropriate developer solution for one to 20 minutes while gently shaking the container. Dry the patterned wafer under a stream of nitrogen gas or compressed air.Inspect the wafer under a microscope at 50 times magnification to verify that the desired pattern is well shaped. Then, place the patterned wafer in a pressurized, open-ended tube furnace. Set the flow rate for the first 15 minutes of the sequence to 1.5 times the volume of the furnace tube per minute and then to the furnace tube volume per minute for the remainder of the sequence.Set a sequence of ramping to 300 degrees Celsius at five degrees Celsius per minute, holding at 300 degrees Celsius for one hour, ramping to 900 degrees Celsius at the same rate and holding for one hour, and then cooling to 300 degrees Celsius at 10 degrees Celsius per minute. Then, run the heating and cooling sequence. Once the sequence has completed, wait for the pyrolyzed sample to cool to room temperature under a stream of nitrogen gas.Then, turn off the furnace and gas flow. Then, carefully remove the pyrolyzed sample from the furnace and proceed to characterization. To begin fabricating a hair-derived 3D carbon structure, wash a sample of human hair with deionized water.Dry the hair sample under a stream of nitrogen gas. Obtain a silicon wafer or a ceramic boat. Arrange the individual hairs in the desired configuration on the wafer or in the boat.If using a silicon wafer, fix the hairs to the wafer with epoxy-based polymer. Then, place the sample in a pressurized, open-ended tube furnace. Run the pyrolysis sequence to first stabilize and then carbonize the sample.Allow the sample to cool to room temperature under a flow of nitrogen. Then, carefully remove the sample from the furnace, using tweezers when necessary, and proceed to characterization. Hair-derived carbon microfibers were prepared in various patterns, depending on the initial arrangement of the hair sample.Energy-dispersive X-ray spectroscopy and Raman spectroscopy were performed before and after pyrolysis. Only two peaks corresponding to the D and G bands appeared in the Raman spectrum after pyrolysis. The intensity ratio between the peaks indicated that the microstructures were primarily composed of glassy carbon.Electrochemical sensors were fabricated using bare carbon, carbon nanotubes, or the hair-derived carbon fibers. Cyclic voltammetry of dopamine and ascorbic acid solutions showed that the electrode incorporating the hair-derived carbon fibers showed improved performance compared to the bare carbon, though they did not match the performance of carbon nanotubes. I hope that this short video on carbon MEMS inspires many of you to explore the process by yourselves.Indeed, there is many, many more applications that I can see coming out of this simple process. This can range from novel batteries, new fuel cells, new sensors, et cetera. Perhaps, overtaking silicon as the most important MEMS material.

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Engineering

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses triangulation between matching points in two views of the same scene at different angles to compute depth.&#160;However, unlike a stereo-based method, DFP uses a digital video projector to replace one of the cameras1. The projector rapidly projects a known sinusoidal pattern onto the subject, and the surface of the subject distorts these patterns in the camera&#8217;s field of view. Three distorted patterns (fringe images) from the camera can be used to compute the depth using triangulation.
Unlike other 3D measurement methods, DFP techniques lead to systems that tend to be faster, lower in equipment cost, more flexible, and easier to develop.&#160;DFP systems can also achieve the same measurement resolution as the camera.&#160;For this reason, DFP and other digital structured light techniques have recently been the focus of intense research (as summarized in1-5). Taking advantage of DFP, the graphics processing unit, and optimized algorithms, we have developed a system capable of 30&#160;Hz 3D video data acquisition, reconstruction, and display for over 300,000 measurement points per frame6,7.&#160;Binary defocusing DFP methods can achieve even greater speeds8.
Diverse applications can benefit from DFP techniques. Our collaborators have used our systems for facial function analysis9, facial animation10, cardiac mechanics studies11, and fluid surface measurements, but many other potential applications exist.&#160;This video will teach the fundamentals of DFP techniques and illustrate the design and operation of a binary defocusing DFP system.

This video describes the fundamentals of digital fringe projection techniques, which provide dense 3D measurements of dynamically changing surfaces.&#160;It also demonstrates the design and operation of a high-speed binary defocusing system based on these techniques.

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses ...

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

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

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

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

Fabrication and Characterization of Superconducting Resonators

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

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

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

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (&lt;2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6&#8729;H2O). Based on its ability to adsorb Ni2+, as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications.

A protocol for the parallel production of precipitated calcium carbonate and zeolitic material from blast furnace slag via mineral carbonation and alkaline hydrothermal conversion, respectively, is presented. The performance of the zeolitic material towards nickel adsorption is tested.

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with ...

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2&#183;g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

A protocol for fabricating porous, nanostructured yttria-stabilized-zirconia (YSZ) scaffolds at temperatures between 1,000 &#176;C and 1,400 &#176;C is presented.

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex donor-acceptor emitters is presented. With a step-by-step procedure, readers will be able to repeat and produce OLED devices based on simple organic emitters. A patterning procedure allowing the creation of personalized indium tin oxide (ITO) shape is shown. This is followed by the evaporation of all layers, encapsulation and characterization of each individual device. The end goal is to present a procedure that will give the opportunity to repeat the information presented in cited publication but also using different compounds and structures in order to prepare efficient OLEDs.

A protocol for the production of simple structured organic light-emitting diodes (OLEDs) is presented.

A method for producing simple and efficient thermally-activated delayed fluorescence organic light-emitting diodes (OLEDs) based on guest-host or exciplex ...

Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for applications in two-dimensional nanoelectronics devices. Although many methods to synthesize SnSe nanocrystals have been developed, a simple way to fabricate large-sized single-layer SnSe flakes remains a great challenge. Herein, we show the experimental method to directly grow large-sized single-layer rectangular SnSe flakes on commonly used SiO2/Si insulating substrates using a straightforward two-step fabrication method in an atmospheric pressure quartz tube furnace system. The single-layer rectangular SnSe flakes with an average thickness of ~6.8 &#197; and lateral dimensions of about 30 &#181;m &#215; 50 &#181;m were fabricated by a combination of vapor transport deposition technique and nitrogen etching route. We characterized the morphology, microstructure, and electrical properties of the rectangular SnSe flakes and obtained excellent crystallinity and good electronic properties. This article about the two-step fabrication method can help researchers grow other similar two-dimensional, large-sized, single-layer materials using an atmospheric pressure system.

A protocol is presented demonstrating a two-step fabrication technique to grow large-sized single-layer rectangular shaped SnSe flakes on low-cost SiO2/Si dielectrics wafers in an atmospheric pressure quartz tube furnace system.

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for ...

Multi-material Ceramic-Based Components &#8211; Additive Manufacturing of Black-and-white Zirconia Components by Thermoplastic 3D-Printing (CerAM - T3DP)

To combine the benefits of Additive Manufacturing (AM) with the benefits of Functionally Graded Materials (FGM) to ceramic-based 4D components (three dimensions for the geometry and one degree of freedom concerning the material properties at each position) the Thermoplastic 3D-Printing (CerAM -&#160;T3DP) was developed. It is a direct AM technology which allows the AM of multi-material components. To demonstrate the advantages of this technology black-and-white zirconia components were additively manufactured and co-sintered defect-free.
Two different pairs of black and white zirconia powders were used to prepare different thermoplastic suspensions. Appropriate dispensing parameters were investigated to manufacture single-material test components and adjusted for the additive manufacturing of multi-color zirconia components.

Here we describe a protocol for additively manufacturing black-and-white zirconia components by Thermoplastic 3D-Printing (CerAM -&#160;T3DP) and co-sintering defect-free.

To combine the benefits of Additive Manufacturing (AM) with the benefits of Functionally Graded Materials (FGM) to ceramic-based 4D components (three ...

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication FFF of Metal-Ceramic Components

This study shows multi-material additive manufacturing (AM) using fused filament fabrication (FFF) of stainless steel and zirconia.

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with ...