CdTe Nanowires by Au-Catalyzed Metalorganic Vapor Phase Epitaxy
CdTe Nanowires by Au-Catalyzed Metalorganic Vapor Phase Epitaxy
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DOI：
10.1021/acs.nanolett.7b00719
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发表时间：
2017-07-01
期刊：
影响因子：
10.8
通讯作者：
Lovergine, Nico
中科院分区：
文献类型：
--
作者：
Di Carlo, Virginia;Prete, Paola;Lovergine, Nico
我们报告的第一个金催化生长的碲化镉纳米线的金属有机气相外延。通过单独的前体流动工艺获得纳米线，其中（i）二异丙基碲化物（（Pr 2 Te）-Pr 1）首先流过反应器以确保形成液体Au-Te合金液滴，和（ii）在用纯H-2吹扫以从蒸气和生长表面除去未反应的（Pr 2 Te）-Pr 1分子之后，（iii）将二甲基镉（Me 2Cd）供应到蒸气中，使得Cd原子可以进入催化剂液滴，导致纳米线自组装。CdTe纳米线在（111）B-GaAs衬底上在485和515 ℃之间生长，后者预先沉积有2 μ m厚的（111）取向的CdTe缓冲层，在该缓冲层上提供Au纳米颗粒。生长的CdTe纳米线是垂直的（[111]对齐）恒定直径的直段，并在其尖端显示出富含Au的纳米液滴，液滴和纳米线之间的接触角类似于130度。纳米线的轴向生长速率出现动力学限制的活化能类似于57千卡/摩尔。然而，生长速率变成独立的纳米线的直径。目前的数据解释的理论模型解释的纳米线的生长，通过扩散运输的Te吸附原子的假设下，它们的生长过程中发生的Me 2Cd流的过程步骤。单根纳米线的低温阴极射线发光光谱。显示出典型的锌共混物CdTe沿着的良好分辨的带边发射，具有主带峰。在1.539eV处。
We report on the first Au-catalyzed growth of CdTe nanowires by metalorganic vapor phase epitaxy. The nanowires were obtained by a separate precursors flow process in which (i) di-isopropyl-telluride ((Pr2Te)-Pr-i) was first flowed through the reactor to ensure the formation, of liquid Au-Te alloy droplets, and (ii) after purging with pure H-2 to remove unreacted (Pr2Te)-Pr-i molecules from the vapor and the growth surface, (iii) dimethylcadmium (Me2Cd) was supplied to the vapor so that Cd atoms could enter the catalyst droplets, leading to nanowire self-assembly. CdTe nanowires were grown between 485 and 515 degrees C on (111)B-GaAs substrates, the latter preliminary deposited with a 2 mu m thick (111)-oriented CdTe buffer layer,onto which Au nanoparticles were provided. As-grown CdTe nanowires were vertical ([111]-aligned) straight segments of constant diameter and showed an Au-rich nanodroplet at their tips, the contact angle between the droplets and the nanowires being similar to 130 degrees. The nanowire axial growth rate appeared kinetics-limited with an activation energy similar to 57 kcal/mol. However, the growth rate turned independent from the nanowire diameter. Present data are interpreted by a theoretical model explaining the nanowire growth, through the diffusion transport of Te adatoms under the assumption that their growth occurs during the Me2Cd-flow process step. Low-temperature cathodoluminescence spectra recorded from single nanowires. showed a well-resolved band-edge emission typical of zincblend CdTe along with a dominant band peaked. at 1.539 eV.