新型InAsSb纳米线外延生长及其光电特性研究

Semiconducting nanowires has played an important role in low-dimensional electronic devices, quantum devices and study of novel optoelectronic devices. Particularly, III-V narrow-band-gap materials like InAs, InSb and InAsSb draw more and more attention for their potential applications in optical fiber communication, high-speed electronic devices, photodetectors, bio-sensors, solar cells and many other fields. In this work, large-area InAsSb NWs and corresponding core/shell heterostructures will be synthesized utilizing a simple and low-cost chemical vapor deposition (CVD) method. The preparation conditions, structures and properties of nanowires will be studied first. Combined with high resolution transmission electron microscopy, micro-nano processing and microscopic optoelectronic characterization methods, optimal controllable nanowires growth processes will be obtained. In addition, we will fabricate photodetectors based on InAsSb NWs and hetero-structure NWs. Output and transfer electrical transport characteristics, threshold voltage, sub-threshold slope, field effect mobility, photoconductive gain, responsivity, specific detectivity as well as other performance parameters of the fabricated devices will be performed, analyzed and discussed. Influence mechanisms of surface defect states induced by the microstructure of the materials on ballistic transport properties, rectifying properties, optoelectronic response, and optoelectronic detection performance will also be studied. This work would provide basic guidance for development of novel high-performance NWs optoelectronic devices.

半导体纳米线在各种低维功能电子器件、量子器件的研究和应用方面扮演着重要的角色，尤其是以砷化铟（InAs）、锑化铟（InSb）及三元化合物InAsSb等为代表的Ⅲ-Ⅴ族窄带隙材料在光纤通讯、高速电子器件、光电探测器、生物传感器、以及太阳能电池等诸多领域有着广阔的潜在应用价值。本项目将利用化学气相沉积方法制备大面积InAsSb纳米线及其异质结（核/壳）纳米线，结合高分辨透射电镜、微纳加工和显微光电表征手段，获得纳米线的制备条件、结构及物性，优化可控的纳米线生长工艺，进而制备基于InAsSb纳米线的光电探测器。测试器件的输出和转移特性、阈值电压、亚阈值斜率、场效应迁移率、光电导增益、响应率以及比探测率等性能参数，探究材料微观结构诱导的表面缺陷态对器件的弹道输运特性、整流特性、光电响应特性、光电探测性能的影响机理，为制备新型高性能光电器件提供基础指导。

准一维半导体纳米线为载流子提供了高速的传输通道，在探测器、太阳电池和晶体管等光电子器件的研究和应用中发挥着重要的作用。InAs、InAsSb等窄带隙的纳米线材料具有宽吸收波段、高电子迁移率等优异的性质，因而受到广泛的关注。本项目生长了InAsSb等纳米线材料并基于单根InAsSb纳米线及其异质结纳米线制备了背栅场效应晶体管。通过光电表征获得了纳米线的阈值电压、亚阈值斜率、场效应迁移率、以及响应率等特性参数，并进一步研究了纳米线晶体管的光电响应特性。另外，我们制备了GaAs/AlGaAs纳米线光电探测器，通过结合耗尽层和二维空穴管道，与纯GaAs器件相比，其响应度增加了18倍（约0.199 A/W）且探测率增加5倍（5.8×10^10 cmHz^1/2W^-1）。证明了通过有效的结合耗尽层和二维空穴管道可以获得高性能的纳米线光电探测器。针对InAsSb纳米线的响应波段问题，综述了三种极具代表性的拓宽InAs纳米线及其异质结结构截止波长的解决方案，其中包括可见光辅助红外光电探测技术，垂直纳米线阵列技术以及调整Sb组分合成InAsSb纳米线的能带工程。此外，从纳米线低维结构的生长过程和材料的基本特性出发，讨论了晶体相、迁移率、形貌、表面态和金属接触。总结对比了应用于InAs纳米线中波红外光电探测器的最新光电技术，对纳米线技术发展路线提出初步建议及展望，为在宽光谱范围内开发下一代高性能光电探测器提供了参考。