Exploring the functionality of Al-catalyzed Si nanowires

研究了用于高迁移率场效应管(HEMT)和光伏电池的气-液-固三相法Al催化硅纳米线(NWS)。通过简单的异地生长条件成功地解决了Al催化剂快速氧化的主要挑战，从而有可能扩大工艺规模，同时防止由于催化剂污染而导致的深能级陷阱的形成。铝催化的SiNW生长在100微米和60微米厚的纸薄抛光和刻蚀的Si(111)晶片上，具有最大限度地减少界面缺陷和光吸收损失的能力。与用金刚石浆料抛光的标准方法相比，深度湿法刻蚀是制备薄硅片的一种简单技术。优化了掺锰CsPbCl3钙钛矿纳米晶与CsPbCl3钙钛矿纳米晶混合纳米结构制备具有同质结结构、提高功率转换效率的薄硅纳米晶太阳电池的工艺条件，并利用Al催化剂成功地实现了Si/Ge核壳纳米晶异质结的空穴气体积累。设计了p型硅和本征Ge异质结的II类能带排列，用于在Ge沟道中诱导空穴-气体积累，以抑制杂质和表面散射。Al催化SiNW具有垂直生长可控、表面光滑、Al掺杂自动化等独特特性，为垂直SiNW HEMT器件的应用提供了重要的优势。

Al-catalyzed Si nanowires (NWs) formed by vapor-liquid-solid growth for high mobility field-effect transistor (HEMT) and photovoltaic cell applications were parallelly investigated. Successfully addressing the major challenge of rapid Al catalyst oxidation by ex-situ and uncomplicated growth conditions allows for the potential to scale up the process while preventing the formation of deep-level traps resulting from catalyst contamination.Al-catalyzed SiNWs grown on paper-thin polished and etched Si(111) wafers of 100 um- and 60 um-thick with high proficiency for minimizing interfacial defects and light absorption loss has been accomplished. Deep wet etching was observed as a simple technique for thin Si wafer preparation compared to the standard method of polishing by diamond slurry. Fabrication of thin Si NW solar cells with homojunction structure toward enhanced power conversion efficiency by hybrid nanostructures with Mn-doped CsPbCl3 perovskite nanocrystals using a simple drop-casting method has been optimized.Hole-gas accumulation of Si/Ge core-shell NW heterostructures using Al-catalyst for core SiNW synthesis was successfully demonstrated. Type-II band alignment of p-type Si and intrinsic Ge heterojunction has been designed for induced hole-gas accumulation in the Ge channel to suppress impurity and surface scattering. The unique characteristics of controllable vertical growth and smooth surface with automated Al doping in Al-catalyzed SiNWs grant major advantages for the application of vertical SiNW-based HEMT devices.