Name: atmospheric pressure fabrication of large-sized single-layer rectangular snse flakes
Uploaded: 2018-03-21T13:30:00
Description: Watch this Scientific Journal Video about Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes at JoVE.com

This research was supported by the 1,000 Talents Program for Young Scientists of China, National Natural Science Foundation of China (Grant No. 51472164), the A*STAR Pharos Programme (Grant No. 152 70 00014), and facility support from the NUS Center for Advanced 2D Materials.

Caution: Some of the chemical agents and gases used in this work are toxic, carcinogenic, flammable, and explosive. Please use all appropriate safety practices when performing a vapor transport deposition including the use of engineering controls (fume hood) and personal protective equipment (safety glasses, professional protective masks, gloves, lab coat, full length pants, and closed-toe shoes).
1. Auto-Tune Function of Temperature Controller Parameters
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Here, the combination of a vapor transport deposition method and a nitrogen etching technique in an atmospheric pressure system is first reported. In this protocol, the critical steps are the section of the fabrication of single-layer SnSe flakes.
Although the bulk samples can be etched to form a high-quality single-layer sample, the thickness of the bulk samples should be uniform and the decomposition temperature of bulk samples should be higher than the etching temperature. The resulting sam...

Research into two dimensional (2D) materials has bloomed in recent years since the successful isolation of graphene, due to the possibility of 2D materials having superior electrical, optical, and mechanical properties over their bulk counterparts1,2,3,4,5. 2D materials show promising applications in optoelectronic and electronic devices6,7, catalysis and water splitting8,9, surface-enhanced Raman scattering sensing10,11, etc. The large family of layered materials which can be exfoliated into 2D materials show great diversity, ranging from the semi-metallic graphene to the semiconducting transition-metal dichalcogenides (TMDs) and black phosphorus (BP) to the insulating hexagonal boron nitride (h-BN). These materials and their heterostructures have been well studied in recent years, and have exhibited many novel properties and applications12. Other less studied, but equally promising 2D layered materials in the IIIA-VIA (GaS, GaSe, and InSe)13,14 and IVA-VIA (GeS, GeSe, and SnS)15,16,17 families have also recently received attention.
SnSe belongs to the IVA-VIA group and crystallizes in an orthorhombic structure, with the atoms arranged in the pnma space group and buckled within the layer, like the crystal structure of phosphorene. SnSe is a narrow gap semiconductor with a band gap of 0.6 eV, but is more well known for its more unique thermoelectric properties, as it is reported to have a very high ZT (thermoelectric figure of merit) value of 2.6 at 923 K18,19, which has been attributed to its unique electronic structure and low thermal conductivity. While bulk SnSe crystals are available commercially and can be grown by known methods, such as the Bridgeman-Stockbarger method20 or the chemical vapor transport method21, growing large sized few-layer and single-layer SnSe on dielectric substrates is more challenging. There are many substrates to support 2D material growth, such as highly oriented pyrolytic graphite (HOPG), mica, SiO2, Si3N4, and glass. Low-cost SiO2 dielectrics are the most commonly used substrate, as these allow the fabrication of field-effect transistors, where the dielectrics serve as part of the electrical back gate. In our experience, unlike graphene and TMDs, it is difficult to obtain few-layer or single-layer SnSe flakes by the micromechanical exfoliation method, as bulk SnSe has a high interlayer binding energy22 of 32 meV/&#197;2, which leads to thick layers, even along the edges of the exfoliated flakes. Therefore, to study the novel electronic properties of few layer and single layer SnSe, a new, simple, and low-cost synthetic method to prepare high quality large-sized single-layer SnSe crystals on insulating substrates is required, especially since SnSe has shown great promise as a candidate for thermoelectric applications for energy conversion in the low and moderate temperature range19.
Several researchers have developed methods to synthesize high quality SnSe crystals. Liu et al.23 and Franzman et al.24 used a solution-phase method to synthesize SnSe nanocrystals of different shapes, such as quantum dots, nanoplates, single crystalline nanosheets, nanoflowers, and nanopolyhedra using SnCl2 and alkyl-phosphine-selenium or dialkyl diselenium as precursors. Baumgardner et al.25 synthesized colloidal SnSe nanoparticles by injecting bis[bis(trimethylsilyl)amino]tin(II) into hot trioctylphosphine, and they obtained nanocrystals of ~4-10 nm in diameter. Boscher et al.26 used an atmospheric pressure chemical vapor deposition technique to obtain SnSe films on glass substrates using tin tetrachloride and diethyl selenide precursors with a tin tetrachloride ratio 10 larger than diethyl selenide, and their synthesized SnSe films were about 100 nm thick and silver-black in appearance. Zhao et al.27 used vapor transport deposition in a low vacuum system and synthesized single-crystal SnSe nanoplates on mica substrates and obtained square nanoplates of 1-6 &#181;m. However, obtaining single-layer SnSe crystals are not possible using these techniques. Li et al.28 successfully synthesized single-layer single-crystal SnSe nanosheets using a one-pot synthetic method with SnCl4 and SeO2 precursors. However, they were only able to obtain a lateral size of about 300 nm for their nanosheets. We have recently published our method to grow high quality, large-sized single-layer SnSe crystals which are phase pure29. This detailed protocol is intended to help new practitioners to grow other large-sized high-quality ultrathin 2D materials using this methodology.

<table border="0" cellpadding="0" cellspacing="0" width="1083">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">SnSe powder&#160;&#160;</td>
			<td style="width:295px;">Sigma-Aldrich</td>
			<td style="width:159px;">1315-06-6</td>
			<td style="width:347px;">(99.999%) toxic, carcinogenic</td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:283px;">Ar gas</td>
			<td style="width:295px;"></td>
			<td style="width:159px;"></td>
			<td>explosive</td>
		</tr>
		<tr height="32">
			<td height="32" style="height:32px;width:283px;">H2 gas</td>
			<td style="width:295px;"></td>
			<td style="width:159px;"></td>
			<td>flammable, explosive</td>
		</tr>
		<tr height="32">
			<td height="32" style="height:32px;">SiO2/Si wafer</td>
			<td style="width:295px;"></td>
			<td style="width:159px;"></td>
			<td>300 nm thick SiO2 on heavily doped Si</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acetone</td>
			<td style="width:295px;">Sigma-Aldrich</td>
			<td>67-64-1</td>
			<td>toxic, flammable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Isopropanol</td>
			<td style="width:295px;">Sigma-Aldrich</td>
			<td>67-63-0</td>
			<td>flammable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Quartz tube</td>
			<td>Dongjing Quartz Company, China</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Ceramic boat</td>
			<td style="width:295px;">Dongjing Quartz Company, China</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Optical microscope</td>
			<td style="width:295px;">Olympus, BX51</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Atomic force microscopy</td>
			<td style="width:295px;">Bruker&#160;</td>
			<td style="width:159px;"></td>
			<td>Using FastScan-A probe type&#160; and ScanAsyst-air</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Scanning electron microscopy&#160;</td>
			<td style="width:295px;">JEOL JSM-6700F</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">transmission electron microscopy</td>
			<td style="width:295px;">FEI Titan</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Tube furnace</td>
			<td style="width:295px;">MTI Corporation</td>
			<td style="width:159px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

Schematic diagrams of the experimental apparatus, optical images, atomic force microscopy (AFM) images, scanning electron microscopy (SEM) images, and transmission electron microscopy (TEM) images of the fabricated SnSe flakes are shown in Figure 1, Figure 2, and Figure 3. The optical images are performed by a traditional optical microscope. The eyepiece lens is 10X, and the objective lens is 20X, 50...

Watch this Scientific Journal Video about Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes at JoVE.com

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

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 ...

The overall goal of the synthetic method of combining a vapor transport deposition technique and nitrogen etching method in an atmospheric pressure system is to demonstrate fabrication of high-quality, large-sized single-layer materials on dielectric substrates. This method provides a general structure for the growth of two-dimensional lines the size of single-layer materials, such as as tin sulfide, germanium selenide, and indium telleride. The main advantage of this technique is that that large-size single-layer flakes can be grown on low-cost silicon dioxide silicon dielectrics with a vapor transport deposition technique and the nitrogen etching method in an atmospheric pressure system.The implications of this technique extend towards the fabrication of other two-dimensional materials because the self-limiting nitrogen etching method can be beneficial to the formation of single layers on both. I first had the idea for this method when I carried out the growth of tungsten diselenide, tin selenide, high-production under nitrogen atmosphere and found that nitrogen etches the material. First, set the target temperature of a horizontal tube furnace to 560 degrees Celsius for one hour and run the furnace.When the temperature approaches 560 degrees Celsius, press the set key for two seconds. Once the parameter HAL"pops up, press the set key for one second to go to the next parameter. Continue to press the set key.After Cont equals three"appears, set it as two. The system starts the autotune function to work out the value for Int, Pro, and LT, and then the system will go to three. When re-autotune is needed, set it as two.Position a new ceramic boat inside a new one-inch diameter quartz tube. Place the quartz tube inside the horizontal tube furnace containing a new two-inch diameter quartz tube. Ensure that both ends of the tubes are firmly fixed and supported.Close the furnace lid and heat the tube furnace to 1000 degrees Celsius over 30 minutes. After maintaining the furnace at 1000 degrees Celsius for 30 minutes, gradually move the tube furnace from one end to the other to heat the whole length of the tube for cleaning the quartz tube wall and the ceramic boat. Following this, allow the tube furnace to cool to room temperature by turning off the furnace.When the furnace is cool, open the furnace lid and take out the ceramic boat and one-inch diameter quartz tube, which can be used for subsequent experiments. Using a diamond scriber, cut a silicon dioxide silicon wafer into 1.5 by two centimeter samples, to be used as growth substrates. Clean the silicon substrates in acetone, isopropanol, and water.Then blow-dry the substrates with nitrogen. Place 0.01 grams of tin selenide powder in the clean ceramic boat. Place a clean silicon dioxide silicon substrate onto the ceramic boat, growth side facing the tin selenide powder.Then position the ceramic boat inside the clean one-inch diameter quartz tube. Place the one-inch diameter quartz tube inside the horizontal tube furnace containing a two-inch diameter quartz tube on the outside, and ensure that the ceramic boat is located upstream of the heating zone of the tube furnace. Tighten the flanges at both ends of the tube and close the vent valve to seal the two-inch diameter quartz tube.Now turn on the pump that connects to the quartz tube and pump the tube to a pressure of approximately one times 10 to the minus two millibar, to remove air and moisture in the tube. Next, open the carrier gas valves, using the gas flow meter to control the gas flows. Introduce 40 sccm argon and 10 sccm hydrogen into the quartz tube until atmospheric pressure is achieved.Then open the vent valves to allow a continuous flow of gas into the quartz tubes. Close the furnace lid and rapidly heat the tube furnace with a 35-degree Celsius per minute heating rate. When the temperature at the center of the furnace approaches 700 degrees Celsius, quickly move the tube furnace to position the tin selenide powder at the center of the furnace, to evaporate the powder and deposit bulk flakes on the silicon dioxide silicon surface.After 15 minutes growth time, open the furnace lid to quickly cool the tube furnace to room temperature. Meanwhile, maximize the flow of the argon-hydrogen carrier gas to help drive the unreacted gas and particles out of the tubes. When the growth process is completed, bulk tin selenide flakes will be obtained on the surface of the silicon dioxide silicon substrates.Place the as-grown bulk sample face up onto a new, clean ceramic boat. Position the ceramic boat inside a new, clean one-inch diameter quartz tube. Place the one-inch diameter quartz tube inside the horizontal tube furnace, containing a two-inch diameter quartz tube, with the ceramic boat located upstream of the heating zone of the tube furnace.Tighten the flanges at both ends of the tube and close the vent valve to seal the two-inch diameter quartz tube. Following this, turn on the pump that connects to the quartz tube and pump the tube to a pressure of approximately one times 10 minus two millibar, to remove air and moisture in the tube. Then turn off the pump.Open the carrier gas valves, using the gas flow meter to control the gas flows. Introduce 50 sccm nitrogen into the quartz tube until atmospheric pressure is achieved. Open the vent valves to allow a continuous flow of gas in the quartz tubes.Next, close the furnace lid and rapidly heat the tube furnace to 700 degrees Celsius in 20 minutes. When the temperature at the center of the furnace approaches 700 degrees Celsius, quickly move the tube furnace to position the bulk sample at the center of the furnace, maintaining the furnace at 700 degrees Celsius for approximately five to 20 minutes to complete the etching process. Following this, open the furnace lid to quickly cool the tube furnace to room temperature.Meanwhile, maximize the flow of nitrogen gas to help drive the unreacted gas and particles out of the tubes. Finally, observe the single-layer rectangular-shaped tin selenide flakes obtained on the surface of the silicon dioxide silicon substrates. Optical microscopy images of the bulk and single-layer tin selenide flakes are shown here.The flakes are approximately rectangular, with dimensions of 30 by 50 micrometers that grow randomly on the silicon dioxide silicon substrates. The AFM image of bulk tin selenide flake revealed a flat surface with a thickness of 54.9 nanometers. The ultra-thin rectangular flakes had a thickness of 6.8 Angstroms, which is close to the theoretical value of single-layer tin selenide.The shape and dimensions of bulk and single-layer tin selenide flakes observed by SEM are in agreement with the optical microscopy images. The EDX spectrum shows a one to 0.92 atomic ratio of tin and selenide in the bulk sample. A TEM image of the transferred tin selenide fragment is shown here.The selected area electron diffraction pattern of a single-layer tin selenide fragment exhibits an orthogonally symmetric diffraction pattern, indicating that the sample is single-crystal in nature. The high-resolution TEM image of the transferred tin selenide fragment shows two orthogonal lattice fringes from the zero negative one one and zero negative one negative one planes. The angle between the lattice fringes is approximately 86.5 degrees, which corresponds to an orthorhombic crystal structure.Once mastered, this technique can be done in about two and a half hours if it is performed properly. While attempting this procedure, it's important to remember to ensure rapid movement of the furnace to the exact location of the operating site and that the etching process is done under nitrogen atmosphere. Following this procedure, other materials like tin sulfide and gallium selenide can be fabricated in order to study the unique properties of these materials.This technique can pave the way for researchers in the field of 2-D material synthesis to explore these single-layer materials'growth and etching mechanism in an atmospheric pressure system. After watching this video, you should have a good understanding of how to fabricate single-layer materials via a vapor transport deposition technique and subsequent nitrogen etching method in an atmospheric pressure system.

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Research

JoVE Journal

Engineering

Fabrication of Spatially Confined Complex Oxides

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from the inherent strong electron correlations that reside within them. These materials can also possess electronic phase separation in which regions of vastly different resistive and magnetic behavior can coexist within a single crystal alloy material. By reducing the scale of these materials to length scales at and below the inherent size of the electronic domains, novel behaviors can be exposed. Because of this and the fact that spin-charge-lattice-orbital order parameters each involve correlation lengths, spatially reducing these materials for transport measurements is a critical step in understanding the fundamental physics that drives complex behaviors. These materials also offer great potential to become the next generation of electronic devices 1-3. Thus, the fabrication of low dimensional nano- or micro-structures is extremely important to achieve new functionality. This involves multiple controllable processes from high quality thin film growth to accurate electronic property characterization. Here, we present fabrication protocols of high quality microstructures for complex oxide manganite devices. Detailed descriptions and required equipment of thin film growth, photo-lithography, and wire-bonding are presented.

We describe the use of pulsed laser deposition (PLD), photolithography and wire-bonding techniques to create micrometer scale complex oxides devices. The PLD is utilized to grow epitaxial thin films. Photolithography and wire-bonding techniques are introduced to create practical devices for measurement purposes.

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from ...

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing

The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, spin-flip scattering) is described, using experiments on GaMnAs as a prototype III-Mn-V system.&#160; Spectrally-resolved and time-resolved experimental configurations are described, including the use of zero-background autocorrelation techniques for pulse optimization.&#160; The etching process used to prepare GaMnAs samples for four-wave mixing experiments is also highlighted.&#160; The high temporal resolution of this technique, afforded by the use of short (20 fsec) optical pulses, permits the rapid spin-flip scattering process in this system to be studied directly in the time domain, providing new insight into the strong exchange coupling responsible for carrier-mediated ferromagnetism.&#160; We also show that spectral resolution of the four-wave mixing signal allows one to extract clear signatures of (s,p)-d hybridization in this system, unlike linear spectroscopy techniques.&#160;&#160; This increased sensitivity is due to the nonlinearity of the technique, which suppresses defect-related contributions to the optical response. This method may be used to measure the time scale for coherence decay (tied to the fastest scattering processes) in a wide variety of semiconductor systems of interest for next generation electronics and optoelectronics.

The technique of femtosecond four-wave mixing is described, including spectrally-resolved and time-resolved configurations. We illustrate the utility of this technique for the investigation of crucial physical properties in the III-V diluted magnetic semiconductors, afforded by its nonlinearity and high temporal resolution.

The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators &#8212; a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes.

This movie shows how an atmospheric plasma torch can be ignited by microwaves with no additional igniters and provides a stable and continuous plasma operation suitable for plenty of applications.

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

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 ...

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. The reactions of cold plasma with the surrounding atmosphere yield a variety of reactive species, which can define its effectiveness. While efficient development of cold plasma therapy requires kinetic models, model benchmarking needs empirical data. Experimental studies of the source of reactive species detected in aqueous solutions exposed to plasma are still scarce. Biomedical plasma is often operated with He or Ar feed gas, and a specific interest lies in investigation of the reactive species generated by plasma with various gas admixtures (O2, N2, air, H2O vapor, etc.) Such investigations are very complex due to difficulties in controlling the ambient atmosphere in contact with the plasma effluent. In this work, we addressed common issues of &#39;high&#39; voltage kHz frequency driven plasma jet experimental studies. A reactor was developed allowing the exclusion of ambient atmosphere from the plasma-liquid system. The system thus comprised the feed gas with admixtures and the components of the liquid sample. This controlled atmosphere allowed the investigation of the source of the reactive oxygen species induced in aqueous solutions by He-water vapor plasma. The use of isotopically labelled water allowed distinguishing between the species originating in the gas phase and those formed in the liquid. The plasma equipment was contained inside a Faraday cage to eliminate possible influence of any external field. The setup is versatile and can aid in further understanding the cold plasma-liquid interactions chemistry.

An experimental setup was created for the helium-operated kHz frequency plasma jet. The setup includes a cage for the plasma power supply and jet and an in-house built reactor to monitor plasma-induced reactive species without the interference of the ambient atmosphere.

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. ...

New Application of an Atmospheric Pressure Plasma Jet as a Neuro-protective Agent Against Glucose Deprivation-induced Injury of SH-SY5Y Cells

The atmospheric pressure plasma jet (APPJ) has attracted the attention of many researchers from multiple disciplines in recent years because its emissions include multiple types of reactive nitrogen species (RNS) and reactive oxygen species (ROS). Our previous study has shown the cytoprotective effect of the APPJ against oxidative stress-induced injuries. The aim of the present study is to provide a detailed in vitro treatment protocol regarding the neuroprotective applications of helium APPJs on glucose deprivation-induced injury in SH-SY5Y cells. The SH-SY5Y human neuroblastoma-derived cell line was maintained in RPMI 1640 medium supplemented with 15% fetal calf serum. The culture medium was then changed to RPMI 1640 without glucose before APPJ treatment. After a 1 h incubation in a cell incubator, cell viability was determined using Cell Counting Kit 8. The results showed that, compared to the glucose deprivation group, cells treated with APPJ exhibited significantly increased cell viability in a dose-dependent manner, with 8 s/well observed as an optimal dose. Meanwhile, helium flow had no effect on the glucose deprivation-induced cell impairment. Our results indicated that APPJ could be potentially used as a treatment method for the diseases in the central nervous system related to glucose deprivation. This protocol could also be used as a cytoprotective application for other cells with different impairments, but the cell culture and APPJ treatment conditions should be readjusted, and the treatment dose must be relatively low.

A protocol for the neuroprotective application of low-dose atmospheric pressure plasma treatment on glucose deprivation-induced SH-SY5Y injuries.

The atmospheric pressure plasma jet (APPJ) has attracted the attention of many researchers from multiple disciplines in recent years because its emissions ...

Nerve Stem Cell Differentiation by a One-step Cold Atmospheric Plasma Treatment In Vitro

As the development of physical plasma technology, cold atmospheric plasmas (CAPs) have been widely investigated in decontamination, cancer treatment, wound healing, root canal treatment, etc., forming a new research field named plasma medicine. Being a mixture of electrical, chemical, and biological reactive species, CAPs have shown their abilities to enhance nerve stem cells differentiation both in vitro and in vivo and are becoming a promising way for neurological disease treatment in the future. The much more exciting news is that using CAPs may realize one-step, and safely directed, differentiation of neural stem cells (NSCs) for tissue transportation. We demonstrate here the detailed experimental protocol of using a self-made CAP jet device to enhance NSC differentiation in C17.2-NSCs and primary rat neural stem cells, as well as observing the cell fate by inverted and fluorescence microscopy. With the help of immunofluorescence staining technology, we found both the NSCs showed an accelerated differential rate than the untreated group, and ~75% of the NSCs selectively differentiated into neurons, which are mainly mature, cholinergic, and motor neurons.

Nerve Stem Cell Differentiation by a One-step Cold Atmospheric Plasma Treatment In Vitro

This protocol aims to provide detailed experimental steps of a cold atmospheric plasma treatment on neural stem cells and immunofluorescence detection for differentiation enhancement.

As the development of physical plasma technology, cold atmospheric plasmas (CAPs) have been widely investigated in decontamination, cancer treatment, ...

Fabrication of Compressed Hosiery and Measurement of its Pressure Characteristic Exerted on the Lower Limbs

This article reports the pressure characteristic measurement of compressed hosiery via direct and indirect methods. In the direct method, an interface sensor is used to measure the pressure value exerted on the lower limbs. In the indirect method, the necessary parameters mentioned by the cone and cylinder model are tested to calculate the pressure value. The necessary parameters involve course density, wales density, circumference, length, thickness, tension, and deformation of the compressed hosiery. Compared with the results of the direct method, the cone model in the indirect method is more suitable for calculating the pressure value because the cone model considers the change in radius of the lower limb from the knee to the ankle. Based on this measurement, the relationship among fabrication, structure, and pressure is further investigated in this study. We find that graduation is the main influence that can change the wales density. On the other hand, elastic motors directly affect the course density and the circumference of the stockings. Our reported work provides the fabrication-structure-pressure relationship and a design guide for gradually compressed hosiery.

This article reports fabrication, structure and pressure measurement of compressed hosiery by employing direct and indirect methods.

This article reports the pressure characteristic measurement of compressed hosiery via direct and indirect methods. In the direct method, an interface ...

Microfluidic Fabrication Techniques for High-Pressure Testing of Microscale Supercritical CO2 Foam Transport in Fractured Unconventional Reservoirs

Pressure limitations of many microfluidic platforms have been a significant challenge in microfluidic experimental studies of fractured media. As a result, these platforms have not been fully exploited for direct observation of high-pressure transport in fractures. This work introduces microfluidic platforms that enable direct observation of multiphase flow in devices featuring surrogate permeable media and fractured systems. Such platforms provide a pathway to address important and timely questions such as those related to CO2 capture, utilization and storage. This work provides a detailed description of the fabrication techniques and an experimental setup that may serve to analyze the behavior of supercritical CO2 (scCO2) foam, its structure and stability. Such studies provide important insights regarding enhanced oil recovery processes and the role of hydraulic fractures in resource recovery from unconventional reservoirs. This work presents a comparative study of microfluidic devices developed using two different techniques: photolithography/wet-etching/thermal-bonding versus Selective Laser-induced Etching. Both techniques result in devices that are chemically and physically resistant and tolerant of high pressure and temperature conditions that correspond to subsurface systems of interest. Both techniques provide pathways to high-precision etched microchannels and capable lab-on-chip devices. Photolithography/wet-etching, however, enables fabrication of complex channel networks with complex geometries, which would be a challenging task for laser etching techniques. This work summarizes a step-by-step photolithography, wet-etching and glass thermal-bonding protocol and, presents representative observations of foam transport with relevance to oil recovery from unconventional tight and shale formations. Finally, this work describes the use of a high-resolution monochromatic sensor to observe scCO2 foam behavior where the entirety of the permeable medium is observed simultaneously while preserving the resolution needed to resolve features as small as 10 &#181;m.

Microfluidic Fabrication Techniques for High-Pressure Testing of Microscale Supercritical CO2 Foam Transport in Fractured Unconventional Reservoirs

This paper describes a protocol along with a comparative study of two microfluidic fabrication techniques, namely photolithography/wet-etching/thermal-bonding and Selective Laser-induced Etching (SLE), that are suitable for high-pressure conditions. These techniques constitute enabling platforms for direct observation of fluid flow in surrogate permeable media and fractured systems under reservoir conditions.

Pressure limitations of many microfluidic platforms have been a significant challenge in microfluidic experimental studies of fractured media. As a ...