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><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&amp;auml;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&amp;auml;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

Research

JoVE Journal

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

Sputter Growth and Characterization of Metamagnetic B2-ordered FeRh Epilayers

Chemically ordered alloys are useful in a variety of magnetic nanotechnologies. They are most conveniently prepared at an industrial scale using sputtering techniques. Here we describe a method for preparing epitaxial thin films of B2-ordered FeRh by sputter deposition onto single crystal MgO substrates. Deposition at a slow rate onto a heated substrate allows time for the adatoms to both settle into a lattice with a well-defined epitaxial relationship with the substrate and also to find their proper places in the Fe and Rh sublattices of the B2 structure. The structure is conveniently characterized with X-ray reflectometry and diffraction and can be visualised directly using transmission electron micrograph cross-sections. B2-ordered FeRh exhibits an unusual metamagnetic phase transition: the ground state is antiferromagnetic but the alloy transforms into a ferromagnet on heating with a typical transition temperature of about 380 K. This is accompanied by a 1% volume expansion of the unit cell: isotropic in bulk, but laterally clamped in an epilayer. The presence of the antiferromagnetic ground state and the associated first order phase transition is very sensitive to the correct equiatomic stoichiometry and proper B2 ordering, and so is a convenient means to demonstrate the quality of the layers that can be deposited with this approach. We also give some examples of the various techniques by which the change in phase can be detected.

A method to prepare epitaxial layers of ordered alloys by sputtering is described. The B2-ordered FeRh compound is used as an example, as it displays a metamagnetic transition that depends sensitively on the degree of chemical order and the exact composition of the alloy.

变磁B2有序化的FeRh外延层溅射生​​长和表征

Chemically ordered alloys are useful in a variety of magnetic nanotechnologies. They are most conveniently prepared at an industrial scale using ...

科研

工程学

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 ...

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% ...

Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. Conventionally reserved for the fabrication of metal thin films, thermal evaporation deposits bismuth into an array of vertical single crystalline nanowires over a flat thin film of vanadium held at RT, which is freshly deposited by magnetron sputtering or thermal evaporation. By controlling the temperature of the growth substrate the length and width of the nanowires can be tuned over a wide range. Responsible for this novel technique is a previously unknown nanowire growth mechanism that roots in the mild porosity of the vanadium thin film. Infiltrated into the vanadium pores, the bismuth domains (~ 1 nm) carry excessive surface energy that suppresses their melting point and continuously expels them out of the vanadium matrix to form nanowires. This discovery demonstrates the feasibility of scalable vapor phase synthesis of high purity nanomaterials without using any catalysts.

A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented.

铋纳米线阵列通过真空热蒸发无核增长

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

对于新材料的低温磁输运测量先进的实验方法

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

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 ...

Solution-Processed "Silver-Bismuth-Iodine" Ternary Thin Films for Lead-Free Photovoltaic Absorbers

Bismuth-based hybrid perovskites are regarded as promising photo-active semiconductors for environment-friendly and air-stable solar cell applications. However, poor surface morphologies and relatively high bandgap energies have limited their potential. Silver-bismuth-iodine (Ag-Bi-I) is a promising semiconductor for optoelectronic devices. Therefore, we demonstrate the fabrication of Ag-Bi-I ternary thin films using material solution processing. The resulting thin films exhibit controlled surface morphologies and optical bandgaps according to their thermal annealing temperatures. In addition, it has been reported that Ag-Bi-I ternary systems crystallize to AgBi2I7, Ag2BiI5, etc. according to the ratio of the precursor chemicals. The solution-processed AgBi2I7 thin films exhibit a cubic-phase crystal structure, dense, pinhole-free surface morphologies with grains ranging in size from 200 to 800 nm, and an indirect bandgap of 1.87 eV. The resultant AgBi2I7 thin films show good air stability and energy band diagrams, as well as surface morphologies and optical bandgaps suitable for lead-free and air-stable single-junction solar cells. Very recently, a solar cell with 4.3% power conversion efficiency was obtained by optimizing the Ag-Bi-I crystal compositions and solar cell device architectures.

Herein, we present detailed protocols for solution-processed silver-bismuth-iodine (Ag-Bi-I) ternary semiconductor thin films fabricated on TiO2-coated transparent electrodes and their potential application as air-stable and lead-free optoelectronic devices.

无铅光伏吸收剂的溶液处理 "银铋碘" 三元薄膜

Bismuth-based hybrid perovskites are regarded as promising photo-active semiconductors for environment-friendly and air-stable solar cell applications. ...

化学

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

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

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7ÃƒÆ’Ã‚Â¢Ãƒâ€¹Ã¢â‚¬Â 'ÃƒÆ’Ã…Â½ Â´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates

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

Gdba2cu 3 o7 的射频磁控管散射-/la0.67sr 0.67 mno 3 准双层薄膜上的 srtio 3 (sto) 单晶基板上

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

Fabrication of Schottky Diodes on Zn-polar BeMgZnO/ZnO Heterostructure Grown by Plasma-assisted Molecular Beam Epitaxy

Heterostructure field effect transistors (HFETs) utilizing a two dimensional electron gas (2DEG) channel have a great potential for high speed device applications. Zinc oxide (ZnO), a semiconductor with a wide bandgap (3.4 eV) and high electron saturation velocity has gained a great deal of attention as an attractive material for high speed devices. Efficient gate modulation, however, requires high-quality Schottky contacts on the barrier layer. In this article, we present our Schottky diode fabrication procedure on Zn-polar BeMgZnO/ZnO heterostructure with high density 2DEG which is achieved through strain modulation and incorporation of a few percent Be into the MgZnO-based barrier during growth by molecular beam epitaxy (MBE). To achieve high crystalline quality, nearly lattice-matched high-resistivity GaN templates grown by metal-organic chemical vapor deposition (MOCVD) are used as the substrate for the subsequent MBE growth of the oxide layers. To obtain the requisite Zn-polarity, careful surface treatment of GaN templates and control over the VI/II ratio during the growth of low temperature ZnO nucleation layer are utilized. Ti/Au electrodes serve as Ohmic contacts, and Ag electrodes deposited on the O2 plasma pretreated BeMgZnO surface are used for Schottky contacts.

Attainment of high-quality Schottky contacts is imperative for achieving efficient gate modulation in heterostructure field effect transistors (HFETs). We present the fabrication methodology and characteristics of Schottky diodes on Zn-polar BeMgZnO/ZnO heterostructures with high-density two dimensional electron gas (2DEG), grown by plasma-assisted molecular beam epitaxy on GaN templates.

等离子体辅助分子束外延法制备的锌极性 BeMgZnO/氧化锌异质结构肖特基二极管的制备

Heterostructure field effect transistors (HFETs) utilizing a two dimensional electron gas (2DEG) channel have a great potential for high speed device ...

<meta charset="utf8"></head><body>利用机械化学方法合成高 ZT 热电材料

Demonstrating the Simplicity and In Situ Temperature Monitoring of the Mechanochemical Synthesis of Metal Chalcogenides Suitable for Thermoelectrics

Mechanochemical synthesis is an extremely useful strategy to reach thermoelectric materials due to its solvent-free one-step character, as the targeted thermoelectricity (TE) materials in a nanocrystalline format can be prepared by mere high-energy milling of elemental precursors. Nevertheless, the subsequent densification method (e.g., spark plasma sintering or hot pressing) is required afterward, similarly to other synthetic methodologies. In this study, the simplicity of mechanochemical synthesis is&#160;presented for two selected metal chalcogenides, namely copper sulfide (Cu1.8S, digenite) and tin selenide (SnSe, svetlanaite), which are known for high ZT values. These compounds can be prepared via a mechanically induced self-propagating reaction (MSR), which is a combustion-like process instantly yielding the products in a very short timeframe (within 1 min). The occurrence of MSR can be well-tracked by in situ temperature monitoring since an abrupt temperature increase occurs at the moment of MSR. We have developed a device which is capable of monitoring the temperature inside the milling jar every 80 ms during planetary ball milling, and it is therefore possible to very precisely track the moment of MSR ignition. The developed device presents an improvement in the monitoring capabilities in comparison with commercially available analogs. This contribution aims to provide a visual insight into all steps, with simple high-energy ball milling of elements to reach TE materials and in situ temperature monitoring being the central points.

<meta charset="utf8"></head><body>展示了适用于热电的金属硫属化物的机械化学合成的简单性和原位温度监测

Here, we present a protocol to synthesize two metal chalcogenides (Cu1.8S and SnSe) suitable for thermoelectrics via an ultrafast (second-range), solvent-free, and one-step mechanochemical synthesis using elemental precursors. Simultaneously, we demonstrate the monitoring of the temperature in the jar during planetary ball milling in situ by the newly developed device.

展示了适用于热电的金属硫属化物的机械化学合成的简单性和原位温度监测

Mechanochemical synthesis is an extremely useful strategy to reach thermoelectric materials due to its solvent-free one-step character, as the targeted ...

使用射频磁控溅射技术制备Bi₂Te₃ 和Sb₂Te₃ 热电薄膜

副本

摘要

探索更多视频

此视频中的章节

变磁B2有序化的FeRh外延层溅射生长和表征

制造和微流控光机振荡器测试

浓稠钇铁石榴石薄膜的形成使用气溶胶沉积

铋纳米线阵列通过真空热蒸发无核增长

对于新材料的低温磁输运测量先进的实验方法

硫化过渡金属膜制备大面积垂直2D 晶体杂化结构

无铅光伏吸收剂的溶液处理 "银铋碘" 三元薄膜

Gdba₂cu 3 o7 的射频磁控管散射-/la_0.67sr 0.67 mno 3 准双层薄膜上的 srtio 3 (sto) 单晶基板上

等离子体辅助分子束外延法制备的锌极性 BeMgZnO/氧化锌异质结构肖特基二极管的制备

展示了适用于热电的金属硫属化物的机械化学合成的简单性和原位温度监测

使用射频磁控溅射技术制备Bi2Te3 和Sb2Te3 热电薄膜

副本

摘要

探索更多视频

此视频中的章节

变磁B2有序化的FeRh外延层溅射生​​长和表征

制造和微流控光机振荡器测试

浓稠钇铁石榴石薄膜的形成使用气溶胶沉积

铋纳米线阵列通过真空热蒸发无核增长

对于新材料的低温磁输运测量先进的实验方法

硫化过渡金属膜制备大面积垂直2D 晶体杂化结构

无铅光伏吸收剂的溶液处理 "银铋碘" 三元薄膜

Gdba2cu 3 o7 的射频磁控管散射-/la0.67sr 0.67 mno 3 准双层薄膜上的 srtio 3 (sto) 单晶基板上

等离子体辅助分子束外延法制备的锌极性 BeMgZnO/氧化锌异质结构肖特基二极管的制备

展示了适用于热电的金属硫属化物的机械化学合成的简单性和原位温度监测

使用射频磁控溅射技术制备Bi₂Te₃ 和Sb₂Te₃ 热电薄膜

变磁B2有序化的FeRh外延层溅射生长和表征

Gdba₂cu 3 o7 的射频磁控管散射-/la_0.67sr 0.67 mno 3 准双层薄膜上的 srtio 3 (sto) 单晶基板上