作者要感谢马来西亚国民大学研究基金的财政支持:UKM-GGPM-2022-069 进行这项研究。

1. 基材制备
<ol><li>用无绒布擦拭玻璃基材，以去除松散的污垢或碎屑。用水和肥皂清洗玻璃基板，用刷子擦洗玻璃上的任何污垢。</li>
	<li>在烧杯中制备下面列出的所有溶剂，将玻璃基板浸入溶剂中，并在37kHz下相应地超声处理。在80°C下制备甲醇10分钟;丙酮在80°C下10分钟，乙醇在80°C下10分钟，蒸馏（DI）水在80°C下20分钟。 注意: 在通风橱中处理高挥发性化学品。</li>
	<li>用镊子将基材从烧杯中逐个取出，放在干净平坦的表面上，用镊子压住基材，用氮气吹干。</li>
	<li>将底物放在120°C的热板上5-10分钟以蒸发任何残留物。将基材放入紫外线臭氧清洁剂中10分钟。</li>
</ol>2.溅射法
<ol><li>腔室准备<ol><li>从枪上取下铝制护罩，将目标材料放在盖子的中心。拧紧磁控管支架上的盖子，然后放回铝制屏蔽罩。用铝箔盖住腔室、喷枪和样品架的主体。</li>
		<li>通过触摸腔体（短）之间的万用表探头进行短路检查，然后是腔体和枪（短），最后是腔体和目标（打开）。该测试对于确保主体（阳极）和目标（阴极）之间没有电流泄漏是必要的，这会阻碍等离子体的形成。</li>
	</ol></li>
	<li>预溅射<ol><li>关上门并用真空吸尘室吸尘 15 - 30 分钟。在吸尘开始时将门和机身压在一起，以确保门紧闭。确保压力表的读数正在递减。</li>
		<li>打开冷却器系统并设置为 15 °C。 打开泵和制冷按钮，打开与溅射仪表相连的阀门。 注意: 如果没有冷却系统，射频溅射就无法运行。等离子体的形成不会发生。</li>
		<li>将氩气流量设置为 4 sccm 并打开气体拨动开关。等到流量达到设定值。</li>
		<li>将旋转设置为 10 rpm 并打开旋转拨动开关。按 下电源 键打开自动匹配的网络控制器和射频电源。</li>
		<li>在自动匹配网络控制器上，通过按 最小/最大 按钮并将按钮从 手动 按为 自动，将负载和调谐分别设置为 50 W。</li>
		<li>在射频电源上，将射频功率设置为 50 W，然后按 下开始 按钮。将计时器设置为 15 分钟。</li>
		<li>关闭射频电源和旋转。将氩气流量设置为 0 并关闭拨动开关。关闭真空吸尘器。 注意: 等到氩气流量达到 0.1 sccm 后再关闭真空。</li>
		<li>通风以打开腔室。在排气前确保涡轮分子泵 （TMP） 处于关闭状态。TMP 运行时排气会损坏系统。</li>
		<li>打开腔室并加载基板。将基板放在旋转样品架的外角，以便更好地沉积，如 图1所示。 注意: 处理腔室内部时戴上口罩和手套，以避免吸入小颗粒材料。</li>
		<li>如 图 2 所示关闭门并吸尘至少 6 小时。较低的基压可提供更好的沉积效果。高真空系统（如溅射工艺）的最佳基压为 1 x 10-5 Torr。</li>
	</ol></li>
	<li>溅射<ol><li>打开冷却器系统并设置为 15 °C。 打开泵和制冷按钮，打开与溅射仪表相连的阀门。</li>
		<li>将旋转设置为 10 rpm 并打开旋转拨动开关。将氩气流量设置为 4 sccm 并打开气体拨动开关。等到流量达到设定值。</li>
		<li>按 下电源 键打开自动匹配的网络控制器和射频电源。</li>
		<li>在自动匹配网络控制器上，通过按 最小/最大 按钮并将按钮从 手动 按为 自动，将负载和调谐分别设置为 50 W。</li>
		<li>在射频电源上，将射频功率设置为 50 W，然后按 下开始 按钮。 注意: 等到氩气流量达到设定值并变得稳定后再打开射频电源。</li>
		<li>检查腔室中是否存在等离子体。等离子体的形成由腔室中发光的紫色光指示。如果打开射频电源后等离子体不存在，请关闭氩气 10 秒，然后重新打开。 重复直到腔室中形成等离子体。</li>
		<li>以每 10 秒间隔 5 W 逐渐增加射频功率，直到达到 75 W。</li>
	</ol></li>
	<li>溅射后<ol><li>关闭射频电源和旋转。关闭自动匹配网络控制器和射频电源。</li>
		<li>将氩气流量设置为 0 并关闭气体拨动开关。关闭真空吸尘器。 注意: 等到氩气流量达到 0.1 sccm 后再关闭真空。</li>
		<li>通风以打开腔室。通风前确保 TMP 已关闭。TMP 运行时排气会损坏系统。</li>
		<li>用镊子取出所有样品，放入干净的培养皿中。 注意: 处理腔室内部时戴上口罩和手套，以避免吸入小颗粒材料。</li>
		<li>清洁腔室并真空 10 - 15 分钟，以保持腔室处于真空状态（无杂质）。</li>
	</ol></li>
</ol><img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66248/66248fig02.jpg"> 图 2:实验设置。 本研究中使用的溅射机的照片。 <a href="https://www.jove.com/files/ftp_upload/66248/66248fig02large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>
3. 表征
<ol><li>使用场发射扫描电子显微镜（FESEM，在3.0 kV工作电压下）进行形貌和横截面扫描，以获得溅射膜的表面微观结构细节和厚度。</li>
	<li>使用FESEM附带的能量色散X射线光谱（EDX）数据对薄膜的成分进行计算。在0.57 T的永磁场中测量Sb2Te3 和Bi2Te3的探头电流分别为0.8 mA和10 mA的霍尔电压，以获得薄膜的载流子浓度和电导率35。</li>
	<li>使用 Isotta 等人使用的类似仪器对塞贝克系数进行平面内测量5。将具有大约 2 cm x 1.25 cm 矩形几何形状的样品安装在装置上。根据 Pt 标准测量 2 触点配置中的绝对塞贝克系数，温度梯度为 ≈25 °C。</li>
</ol>

通过射频溅射将 Bi2Te3 和 Sb2Te3 薄膜沉积在玻璃基板上

作者没有什么可透露的。

本文介绍的技术在设置设备和实施方面没有重大困难。但是，需要强调几个关键步骤。如协议的步骤2.2.10所述，最佳真空条件是生产污染较少的高质量薄膜的关键，因为真空可以去除腔室37中的残留氧气。氧气的存在会导致薄膜出现裂纹，称为应力开裂，表明高真空系统在溅射过程中的重要性38。这也减少了原子39 从靶材到基板的运动中与残余...

热电 （TE） 材料通过塞贝克效应1 将热能转化为电能以及通过帕尔帖冷却2 将热能转化为电能的能力吸引了相当多的研究兴趣。TE材料的转换效率由TE支腿的热端和冷端之间的温差决定。一般来说，温差越大，TE的品质因数越高，其效率越高3。TE 在工作过程中不需要额外的机械部件，不会产生任何废物或污染，使其对环境安全，并被视为绿色能源收集系统。
碲化铋、Bi2Te3 及其合金仍然是最重要的一类 TE 材料。即使在热电发电中，例如废热回收，Bi2Te3 合金也因其在高达 200 °C4 的出色效率而最常用，并且尽管各种 TE 材料的 zT 值超过 2，但在环境温度下仍然是一种出色的 TE 材料5。已发表的几篇论文研究了该材料的TE性质，表明化学计量Bi2Te3具有负塞贝克系数6,7,8，表明n型性质。然而，该化合物可以通过分别与碲化锑（Sb2Te3）和硒化铋（Bi2Se3）合金化来调整为p型和n型，这可以增加它们的带隙并减少双极效应9。
碲化锑，Sb2Te3 是另一种成熟的 TE 材料，在低温下具有很高的品质因数。化学计量 Bi2Te3 是具有 n 型特性的出色 TE，而 Sb2Te3 具有 p 型特性。在某些情况下，TE材料的性质往往取决于材料的原子组成，如n型富Te的Bi2Te3，而p型富Bi2Te3由于BiTe抗位受体的缺陷4。然而，由于 SbTe 反位缺陷的形成能相对较低，即使在富 Teb2Te34 中，Sb2Te3 始终是 p 型。 因此，这两种材料成为制造各种应用的热电发电机p-n模块的合适候选者。
目前的常规TEG由n型和p型半导体的切块锭制成，这些铸块以串联10垂直连接。由于效率低下且笨重、刚性强，它们仅用于利基领域。随着时间的流逝，研究人员开始探索薄膜结构，以获得更好的性能和应用。据报道，薄膜TE由于导热系数低11,12、材料量少且更容易与集成电路12集成，因此比其笨重的同类产品（例如更高的zT）具有优势。因此，受益于纳米材料结构的优势，薄膜热电器件的利基TE研究一直在上升13,14。
薄膜的微纳加工对于获得高性能 TE 材料非常重要。为此，已经研究和开发了各种沉积方法，包括化学气相沉积15、原子层沉积16、17、脉冲激光沉积18、19、20、丝网印刷8、21和分子束外延22。然而，这些技术大多存在运营成本高、生长工艺复杂或材料制备复杂等问题。相反，磁控溅射是一种经济高效的方法，用于生产更致密、晶粒尺寸更小、附着力更好、均匀性高的高质量薄膜 23,24,25。
磁控溅射是基于等离子体的物理气相沉积（PVD）工艺之一，广泛应用于各种工业应用。当向靶材（阴极）施加足够的电压时，溅射工艺起作用，来自辉光放电等离子体的离子轰击靶材，不仅释放二次电子，还释放阴极材料的原子，最终影响基板表面并凝结成薄膜。溅射工艺于 1930 年代首次商业化，并于 1960 年代得到改进，由于其能够使用直流 （DC） 和射频溅射沉积各种材料而引起了极大的兴趣26,27。磁控溅射通过利用磁场克服了低沉积速率和高基板加热冲击。强磁体将等离子体中的电子限制在目标表面或附近，并防止损坏形成的薄膜。这种配置保留了沉积薄膜28的化学计量和厚度均匀性。
使用磁控溅射法制备Bi2Te3和Sb2Te3热电薄膜也得到了广泛的研究，在工艺中加入了掺杂4,29,30和退火31等技术，导致不同的性能和质量。Zheng等[32]的研究采用热诱导扩散法扩散了分别溅射的Ag掺杂Bi和Te层。该方法可以精确控制薄膜的成分，并且通过热感应扩散Te可以防止Te挥发。薄膜的性能也可以通过溅射前的预涂层工艺33来增强，由于高载流子迁移率，导致更好的导电性，从而增强功率因数。除此之外，Chen等[34]的研究通过硒化后扩散反应法掺杂Se，提高了溅射Bi2Te3的热电性能。在此过程中，Se 蒸发并扩散到 Bi-Te 薄膜中形成 Bi-Te-Se 薄膜，其功率因数比未掺杂的 Bi2Te3 高 8 倍。
本文介绍了射频磁控溅射技术在玻璃基板上沉积Bi2Te3 和Sb2Te3 薄膜的实验装置和程序。溅射以自上而下的配置进行，如 图1中的原理图所示，阴极与基板法线成一定角度安装，导致基板的等离子体更加集中和收敛。采用FESEM、EDX、霍尔效应和塞贝克系数等方法系统表征薄膜表面形貌、厚度、成分和热电性能。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66248/66248fig01.jpg"> 图 1:自上而下的配置溅射示意图。 该图的设计符合本研究可用的实际溅射配置，但不是按比例设计的，包括从顶部观察要溅射的玻璃基板的布置。 <a href="https://www.jove.com/files/ftp_upload/66248/66248fig01large.jpg" target="_blank">请点击这里查看此图的较大版本.</a>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetone</td>
			<td>Chemiz (M) Sdn. Bhd.</td>
			<td>1910151</td>
			<td>Liquid, Flammable</td>
		</tr>
		<tr>
			<td>Antimony Telluride, Sb2Te3</td>
			<td>China Rare Metal Material Co.,Ltd</td>
			<td>C120222-0304</td>
			<td>Diameter 50.8 mm, Thickness 6.35 mm, 99.999% purity</td>
		</tr>
		<tr>
			<td>Bismuth Telluride, Bi2Te3</td>
			<td>China Rare Metal Material Co.,Ltd</td>
			<td>CB151208-0501</td>
			<td>Diameter 50.8 mm, Thickness 4.25 mm, 99.999% purity</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Chemiz (M) Sdn. Bhd.</td>
			<td>2007081</td>
			<td>Liquid, Flammable</td>
		</tr>
		<tr>
			<td>Field Emission Scanning Electron Microscope</td>
			<td>Zeiss</td>
			<td>MERLIN</td>
			<td>Equipped with EDX</td>
		</tr>
		<tr>
			<td>Hall effect measurement system</td>
			<td>Aseptec Sdn. Bhd.</td>
			<td>HMS ECOPIA 3000</td>
			<td>-</td>
		</tr>
		<tr>
			<td>Handheld digital multimeter</td>
			<td>Prokits Industries Sdn. Bhd.</td>
			<td>303-150NCS</td>
			<td>-</td>
		</tr>
		<tr>
			<td>HMS-3000</td>
			<td>Aseptec Sdn Bhd.</td>
			<td>HMS ECOPIA 3000</td>
			<td>Hall effect measurement software</td>
		</tr>
		<tr>
			<td>Linseis_TA</td>
			<td>Linseis Messger&#228;te GmbH</td>
			<td>LSR-3</td>
			<td>Linseis thermal analysis software</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Chemiz (M) Sdn. Bhd.</td>
			<td>2104071</td>
			<td>Liquid, Flammable</td>
		</tr>
		<tr>
			<td>RF-DC magnetron sputtering</td>
			<td>Kurt J. Lesker Company</td>
			<td>-</td>
			<td>Customized hybrid system</td>
		</tr>
		<tr>
			<td>Seebeck coefficient measurement system</td>
			<td>Linseis Messger&#228;te GmbH</td>
			<td>LSR-3</td>
			<td>-</td>
		</tr>
		<tr>
			<td>SmartTiff</td>
			<td>Carl Zeiss Microscopy Ltd</td>
			<td>-</td>
			<td>SEM image thickness measurement software</td>
		</tr>
		<tr>
			<td>Ultrasonic bath</td>
			<td>Fisherbrand</td>
			<td>FB15055</td>
			<td>-</td>
		</tr>
		<tr>
			<td>UV ozone cleaner</td>
			<td>Ossila Ltd</td>
			<td>L2002A3-UK</td>
			<td>-</td>
		</tr>
	</tbody>
</table>

fabrication of bi2te3 and sb2te3 thermoelectric thin films using radio frequency magnetron sputtering technique

通过对热电 （TE） 材料的各种研究，薄膜配置比传统的块状 TE 具有优越的优势，包括对弯曲和柔性基板的适应性。已经探索了几种不同的薄膜沉积方法，但磁控溅射由于其高沉积效率和可扩展性而仍然具有优势。因此，本研究旨在通过射频（RF）磁控溅射法制备碲化铋（Bi2Te3）和碲化锑（Sb2Te3）薄膜。薄膜在环境温度下沉积在钠钙玻璃基板上。首先用水和肥皂洗涤基材，用甲醇、丙酮、乙醇和去离子水超声清洗10 min，用氮气和热板干燥，最后在UV臭氧下处理10 min，去除残留物后再进行涂布工艺。使用带有氩气的 Bi2Te3 和 Sb2Te3 溅射靶材，并进行预溅射以清洁靶材表面。然后，将一些干净的基板装入溅射室，并对溅射室进行真空吸尘，直到压力达到 2 x 10-5 Torr。薄膜沉积60 min，氩气流量为4 sccm，射频功率分别为75 W和30 W，Bi2Te3 和Sb2Te3。该方法产生了高度均匀的n型Bi2Te3 和p型Sb2Te3 薄膜。

使用FESEM记录沉积的Bi2Te3 和Sb2Te3 薄膜的横截面显微照片，分别如 图3A 和 图3B所示。整片表面显得均匀光滑。很明显，Bi2Te3 薄膜的晶粒是六边形的，符合Bi2Te3 的晶体结构，而Sb2Te3 薄膜的晶粒由细小的圆形晶粒组成，与Amirghasemi等人36报道的相似。两个?...

作者聚焦:通过射频磁控溅射实现高性能热电薄膜的进展

该手稿描述了一种在玻璃基板上对Bi2Te3 和Sb2Te3 热电薄膜进行射频磁控溅射的协议，该协议代表了一种可靠的沉积方法，具有广泛的应用潜力，并具有进一步发展的潜力。

使用射频磁控溅射技术制备Bi2Te3 和Sb2Te3 热电薄膜

Through various studies on thermoelectric (TE) materials, thin film configuration gives superior advantages over conventional bulk TEs, including ...

我们的研究重点是制造用于热电发电机的高质量薄膜，以回收废热并将其转化为电能。已经研究和开发了各种薄膜沉积技术，包括射频磁控溅射，能够生产出具有更好附着力和高均匀性的高密度、坚固的薄膜。这种方法不需要对目标材料进行熔化和蒸发，使大多数材料无论熔化温度如何都可以沉积，因此优于其他物理气相沉积技术。

fabrication-bi2te3-sb2te3-thermoelectric-thin-films-using-radio

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Engineering

Fabrication of Bi2Te3 and Sb2Te3 Thermoelectric Thin Films using Radio Frequency Magnetron Sputtering Technique

2.5K 次观看.  Universiti Kebangsaan Malaysia. 我们的研究重点是制造用于热电发电机的高质量薄膜，以回收废热并将其转化为电能。已经研究和开发了各种薄膜沉积技术，包括射频磁控溅射，能够生产出具有更好附着力和高均匀性的高密度、坚固的薄膜。这种方法不需要对目标材料进行熔化和蒸发，使大多数材料无论熔化温度如何都可以沉积，因此优于其他物理气相沉积技术。

视频: 作者聚焦:通过射频磁控溅射实现高性能热电薄膜的进展

Fabrication and Testing of Microfluidic Optomechanical Oscillators

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained.

Parametric optomechanical excitations have recently been experimentally demonstrated in microfluidic optomechanical resonators by means of optical radiation pressure and stimulated Brillouin scattering. This paper describes the fabrication of these microfluidic resonators along with methodologies for generating and verifying optomechanical oscillations.

制造和微流控光机振荡器测试

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including ...

科研

工程学

Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk. The primary advantage of AD is that the deposition takes place entirely at ambient temperature; thereby enabling film growth in material systems with disparate melting temperatures. This report describes in detail the processing steps for preparing the powder and for performing AD using the custom-built system. Representative characterization results are presented from scanning electron microscopy, profilometry, and ferromagnetic resonance for films grown in this system. As a representative overview of the capabilities of the system, focus is given to a sample produced following the described protocol and system setup. Results indicate that this system can successfully deposit 11 &#181;m thick yttrium iron garnet films that are &#160;&#62; 90% of the bulk density during a single 5 min deposition run. A discussion of methods to afford better control of the aerosol and particle selection for improved thickness and roughness variations in the film is provided.

This report describes the use of a custom-built system to perform aerosol deposition of thick films of yttrium iron garnet onto sapphire substrates at RT. The deposited films are characterized using scanning electron microscopy, profilometry, and ferromagnetic resonance to give a representative overview of the capabilities of the technique.

浓稠钇铁石榴石薄膜的形成使用气溶胶沉积

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% ...

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can potentially contribute to the exposure of biota and humans. The diffusive gradients in thin films technique is introduced here for in-situ measurements of Pu bioavailability and speciation. A diffusion cell constructed for laboratory experiments with Pu and the newly developed protocol make it possible to simulate the environmental behavior of Pu in model solutions of various chemical compositions. Adjustment of the oxidation states to Pu(IV) and Pu(V) described in this protocol is essential in order to investigate the complex redox chemistry of plutonium in the environment. The calibration of this technique and the results obtained in the laboratory experiments enable to develop a specific DGT device for in-situ Pu measurements in freshwaters. Accelerator-based mass-spectrometry measurements of Pu accumulated by DGTs in a karst spring allowed determining the bioavailability of Pu in a mineral freshwater environment. Application of this protocol for Pu measurements using DGT devices has a large potential to improve our understanding of the speciation and the biological transfer of Pu in aquatic ecosystems.

The technique of diffusive gradients in thin films (DGT) is proposed for speciation studies of plutonium. This protocol describes diffusion experiments probing the behavior of Pu(IV) and Pu(V) in presence of organic matter. DGTs deployed in a karstic spring allow assessment of the bioavailability of Pu.

环境钚的薄膜弥散形态和生物利用度测量

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can ...

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

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

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

欧姆接触制造用聚焦离子束技术和电气特性的半导体层的纳米结构

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

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). In spite of its potential processing capability, the direct AM method has several disadvantages such as high cost, poor surface finish of final products, limitation in material selection, high thermal stress, and anisotropic properties of parts. We propose a cost-effective method to manufacture 3D lattice metals. The objective of this study is to provide a detailed protocol on fabrication of 3D lattice metals having a complex shape and a thin wall thickness; e.g., octet truss made of Al and Cu alloys having a unit cell length of 5 mm and a cell wall thickness of 0.5 mm. An overall experimental procedure is divided into eight sections: (a) 3D printing of sacrificial patterns (b) melt-out of support materials (c) removal of residue of support materials (d) pattern assembly (e) investment (f) burn-out of sacrificial patterns (g) centrifugal casting (h) post-processing for final products. The suggested indirect AM technique provides the potential to manufacture ultra-lightweight lattice metals; e.g., lattice structures with Al alloys. It appears that the process parameters should be properly controlled depending on materials and lattice geometry, observing the final products of octet truss metals by the indirect AM technique.

An indirect additive manufacturing method combining a 3D printing of polymers with a centrifugal casting is outlined for manufacturing 3D octet truss metals (Al and Cu alloys) having a unit cell length of 5 mm with a wall thickness of 0.5 mm.

与超薄切片格金属制造间接使用离心铸造

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) ...

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for Cu(In,Ga)Se2 Solar Cells

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction of degradation mechanisms and prevention of module field failure can consequently decrease investment risks as well as increase the electricity yield. An improved knowledge level can for these reasons significantly decrease the total costs of PV electricity. 
In order to better understand and minimize the degradation of PV modules, the occurring degradation mechanisms and conditions should be identified. This should preferably happen under combined stresses, since modules in the field are also simultaneously exposed to multiple stress factors. Therefore, two 'Combined Stress test with in situ measurement' setups have been designed and constructed. These setups allow the simultaneous use of humidity, temperature, illumination, and electrical biases as independently controlled stress factors on solar cells and minimodules. The setups also allow real-time monitoring of the electrical properties of these samples. This protocol presents these setups and describes the experimental possibilities. Moreover, results obtained with these setups are also presented: various examples about the influence of both deposition and degradation conditions on the stability of thin film Cu(In,Ga)Se2 (CIGS) as well as Cu2ZnSnSe4 (CZTS) solar cells are described. Results on the temperature dependency of CIGS solar cells are also presented.

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for CuIn,GaSe2 Solar Cells

Two &#39;Combined Stress test with in situ measurement&#39; setups, which allow real-time monitoring of accelerated degradation of solar cells and modules, were designed and constructed. These setups allow the simultaneous use of humidity, temperature, electrical biases, and illumination as independently controlled stress factors. The setups and various experiments executed are presented.

就地太阳能电池和模块加速性能退化的监测: 铜 (in, Ga) Se2太阳能电池的实例研究

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction ...

Fabrication of Periodic Gold Nanocup Arrays Using Colloidal Lithography

Within recent years, the field of plasmonics has exploded as researchers have demonstrated exciting applications related to chemical and optical sensing in combination with new nanofabrication techniques. A plasmon is a quantum of charge density oscillation that lends nanoscale metals such as gold and silver unique optical properties. In particular, gold and silver nanoparticles exhibit localized surface plasmon resonances-collective charge density oscillations on the surface of the nanoparticle-in the visible spectrum. Here, we focus on the fabrication of periodic arrays of anisotropic plasmonic nanostructures. These half-shell (or nanocup) structures can exhibit additional unique light-bending and polarization-dependent optical properties that simple isotropic nanostructures cannot. Researchers are interested in the fabrication of periodic arrays of nanocups for a wide variety of applications such as low-cost optical devices, surface-enhanced Raman scattering, and tamper indication. We present a scalable technique based on colloidal lithography in which it is possible to easily fabricate large periodic arrays of nanocups using spin-coating and self-assembled commercially available polymeric nanospheres. Electron microscopy and optical spectroscopy from the visible to near-infrared (near-IR) was performed to confirm successful nanocup fabrication. We conclude with a demonstration of the transfer of nanocups to a flexible, conformal adhesive film.

We demonstrate the fabrication of periodic gold nanocup arrays using colloidal lithographic techniques and discuss the importance of nanoplasmonic films.

用胶体光刻制备周期性金 Nanocup 阵列

Within recent years, the field of plasmonics has exploded as researchers have demonstrated exciting applications related to chemical and optical sensing ...

Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present an advanced method for fabricating ultra-thin color films with improved characteristics. The proposed process addresses several fabrication issues, including large area processing. Specifically, the protocol describes a process for fabricating ultra-thin color films using an electron beam evaporator for oblique angle deposition of germanium (Ge) and gold (Au) on silicon (Si) substrates.&#160; Film porosity produced by the oblique angle deposition induces color changes in the ultra-thin film. The degree of color change depends on factors such as deposition angle and film thickness. Fabricated samples of the ultra-thin color films showed improved color tunability and color purity. In addition, the measured reflectance of the fabricated samples was converted into chromatic values and analyzed in terms of color. Our ultra-thin film fabricating method is expected to be used for various ultra-thin film applications such as flexible color electrodes, thin film solar cells, and optical filters. Also, the process developed here for analyzing the color of the fabricated samples is broadly useful for studying various color structures.

We present a detailed method for fabricating ultra-thin color films with improved characteristics for optical coatings. The oblique angle deposition technique using an electron beam evaporator allows improved color tunability and purity. Fabricated films of Ge and Au on Si substrates were analyzed by reflectance measurements and color information conversion.

用斜角沉积法制备高吸收介质的超薄彩色薄膜

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present ...

Preparation of Large-area Vertical 2D Crystal Hetero-structures Through the Sulfurization of Transition Metal Films for Device Fabrication

We have demonstrated that through the sulfurization of transition metal films such as molybdenum (Mo) and tungsten (W), large-area and uniform transition metal dichalcogenides (TMDs) MoS2 and WS2 can be prepared on sapphire substrates. By controlling the metal film thicknesses, good layer number controllability, down to a single layer of TMDs, can be obtained using this growth technique. Based on the results obtained from the Mo film sulfurized under the sulfur deficient condition, there are two mechanisms of (a) planar MoS2 growth and (b) Mo oxide segregation observed during the sulfurization procedure. When the background sulfur is sufficient, planar TMD growth is the dominant growth mechanism, which will result in a uniform MoS2 film after the sulfurization procedure. If the background sulfur is deficient, Mo oxide segregation will be the dominant growth mechanism at the initial stage of the sulfurization procedure. In this case, the sample with Mo oxide clusters covered with few-layer MoS2 will be obtained. After sequential Mo deposition/sulfurization and W deposition/sulfurization procedures, vertical WS2/MoS2 hetero-structures are established using this growth technique. Raman peaks corresponding to WS2 and MoS2, respectively, and the identical layer number of the hetero-structure with the summation of individual 2D materials have confirmed the successful establishment of the vertical 2D crystal hetero-structure. After transferring the WS2/MoS2 film onto a SiO2/Si substrate with pre-patterned source/drain electrodes, a bottom-gate transistor is fabricated. Compared with the transistor with only MoS2 channels, the higher drain currents of the device with the WS2/MoS2 hetero-structure have exhibited that with the introduction of 2D crystal hetero-structures, superior device performance can be obtained. The results have revealed the potential of this growth technique for the practical application of 2D crystals.

Through the sulfurization of pre-deposited transition metals, large-area and vertical 2D crystal hetero-structures can be fabricated. The film transferring and device fabrication procedures are also demonstrated in this report.

硫化过渡金属膜制备大面积垂直2D 晶体杂化结构

We have demonstrated that through the sulfurization of transition metal films such as molybdenum (Mo) and tungsten (W), large-area and uniform transition ...

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.

薄膜控制研究波浪对液滴冲击动力学的影响薄流动液体薄膜

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