VIA族元素(S, Se, Te)掺杂黑磷单晶的高温高压生长及对其环境稳定性的调控

Black phosphorus (BP) was the only one elemental two dimensional (2D) layer-structured semiconductors so far. However, due to the hydrophilic and easily oxidizable surface, devices based on BP are rapidly degraded when exposed to the air. By using the high temperature and high pressure technique, we have managed to successfully fabricate Tellurium doped single crystal of BP with high quality, and showed that the doping of Te not only suppressed greatly the oxidized erosion and degradation of the BP surface, but also improved the performance of the field effect transistors. In this project, we propose to grown high quality single crystal of BP doped by elements such as S, Se, and Te in group VIA. For all the 2D crystal of BP with different doping elements and doping levels, we are going to measure the thickness, surface morphology, valence and oxidation products after different ageing time, so as to explore the effects and underlying mechanism of the doping on the oxidized erosion of the BP surface. Moreover, for those doped 2D BP crystals, we are going to measure electric/magnetic transportation properties and photoresponse properties such as the carrier mobility, temperature variable Hall resistance magnetoresistance, quantum efficiency etc., as well as the variation of these parameters with ageing time. By analysing these experimental results, we are going to show the best doping element and its optimal level for the improved properties with combined high performance and good stability in ambient, and shed light on the rules and regulation mechanism operating in improving the performance and its environment stability with doping. Eventually we aim to offer experimental and theoretical support for the coming application of BP devices with high performance.

黑磷是目前已知的唯一的单质二维层状高迁移率半导体材料，受到业界大量关注。然而黑磷表面较强的亲水性和易氧化性，导致黑磷器件性能在大气中快速失效。我们前期已经利用高温高压技术制备碲掺杂的高质量黑磷单晶，发现碲的掺杂有效地抑制黑磷表面氧化降解，并提高器件输运性能。本项目拟通过高压高温技术制备S，Se和Te掺杂的高质量黑磷单晶，研究制备掺杂量可控的高质量黑磷单晶的高温高压技术和优化的工艺条件；针对不同掺杂元素和掺杂量的黑磷二维晶体，测定其厚度、表面的形貌、价态和表面的氧化产物等性能参数在大气中的时效性，探索掺杂对其表面氧化腐蚀的影响规律和机制，测定载流子迁移率、变温霍尔和磁电阻、量子效率等电/磁输运和光电响应性能参数以及其在大气环境中的稳定性，获得改善器件综合性能的优化掺杂元素与掺杂量，阐明掺杂调控黑磷性能及其环境稳定性的规律和微观机制，为高性能黑磷器件的未来应用提供实验和理论依据。

黑磷是一种为数不多的单质层状p型半导体材料，因其具有的高迁移率、宽范围可调的直接带隙值、独特的各向异性等优异的性能，在高性能信息存储、能源储存、传感等方面展现了巨大的应用潜力，受到科研界和产业界的持续的关注。然而，黑磷本征上具有较差的环境稳定性，在大气中容易降解而快速失效，限制了黑磷的规模化应用，特别是基于黑磷的器件应用。理论上预期，通过在黑磷中引入额外的原子后，可以在其中形成较强的化学键，有利于其热稳定性及化学稳定性的改善。在本项目中，我们利用高温高压技术对黑磷进行了包括S、Se、Te在内的多种元素掺杂，制备了高质量黑磷单晶，并研究了多种掺杂元素对黑磷稳定性和基于黑磷器件稳定性及性能的影响。通过对形貌、厚度、结构的测试分析，我们发现掺杂在一定程度上能改善黑磷的环境稳定性，然而掺杂元素很难进入到黑磷的晶格中。掺杂量提高后，掺杂元素在黑磷表面形成杂质相，也有利于抑制黑磷在空气环境下的降解。此外，过多的掺杂元素的添加导致黑磷结构不稳定，容易形成磷化物第二相，其中有的具有层状结构，有的是非层状结构。我们也对这些层状和非层状的结构的磷化物的结构和性能开展了部分研究。