Direct Electrodeposition of Crystalline Groups IV and III-V Semiconductors by Electrochemical Liquid-Liquid-Solid Growth

在化学系大分子、超分子和纳米化学项目以及材料研究系固态和材料研究项目的支持下，密歇根大学的Stephen马尔多纳多教授旨在开发一种新的、低能耗的方法，用于制备技术上重要的晶体半导体材料。半导体是制造电池、太阳能电池和超快微电子的重要材料。 目前，需要能量密集的方法来制备高质量的共价半导体。 该项目为研究生和本科生提供电化学，材料科学和与能量转换/存储和微电子学领域相关的先进电子显微镜方法的研究培训。 除了在全国会议上以出版物和演讲的形式传播研究成果外，马尔多纳多教授还打算开发一个新的实验室练习，制作半导体器件，以在本科课程中引入电化学。这项研究探讨了电化学液-液-固（ec-LLS）沉积作为半导体合成和低能量晶体生长方法的应用。 ec-LLS方法的吸引力在于它是一种一锅法，其中液体金属同时用作还原半导体原料的电子源和甚至在低温下生长半导体晶体的介质。 在这个项目中有三个主要的推动力。 第一个推力的目的是确定策略和ec-LLS沉积参数的效果所需的属性在第IV族（锗，硅）宏观晶体和微米/纳米线。 这方面的知识是必不可少的预测控制的形态，晶体学和电子性质的结晶共价半导体通过ec-LLS方法制备。 第二个推力涉及非原位和原位（例如在光学和透射电子显微镜内）分析，以直接和真实的时间跟踪ec-LLS中的成核和晶体生长步骤。 电流-时间数据与特定成核和晶体生长步骤之间的相关性提供了关于各种物理化学和电化学因素对由ec-LLS形成的晶体的影响的真实的时间反馈。第三个重点是了解和控制定制III-V（GaAs，InAs，GaSb，InSb）纳米颗粒和纳米线的ec-LLS工艺。

With the support from the Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry and the Solid State and Materials Research Program of the Division of Materials Research, Prof. Stephen Maldonado of the University of Michigan aims to develop a novel, low-energy method for the preparation of technologically important crystalline semiconducting materials. Semiconductors are important materials for the fabrication of batteries, solar cells, and ultrafast microelectronics. Currently, energy-intensive methods are required for preparing high quality covalent semiconductors. This project provides to graduate and undergraduate students research training in electrochemistry, materials science, and advanced electron microscopic methods relevant to the fields of energy conversion/storage and microelectronics. In addition to disseminating research results in the form of publications and presentations at national conferences, Prof. Maldonado aimes to develop a new laboratory exercise on making semiconductor devices to introduce electrochemistry in the undergraduate curriculum.This research explores the use of electrochemical liquid-liquid-solid (ec-LLS) deposition as a synthetic and low-energy crystal growth method of semiconductors. The appeal of ec-LLS method is that it is a one-pot approach in which liquid metals are used simultaneously as sources of electrons for the reduction of semiconductor feedstock and as media for growing semiconductor crystals even at low temperatures. There are three main thrusts in this project. The first thrust aims to identify strategies and ec-LLS deposition parameters that effect desirable properties in Group IV (Ge, Si) macroscale crystals and micro/nanowires. This knowledge is essential for the predictive control of the morphological, crystallographic, and electronic properties of crystalline covalent semiconductors prepared through ec-LLS method. The second thrust involves ex-situ and in-situ (e.g. within optical and transmission electron microscopes) analyses to follow the nucleation and crystal growth steps in ec-LLS directly and in real time. The correlation between the current-time data and the specific nucleation and crystal growth steps provides real time feedback on the effects of various physicochemical and electrochemical factors on the crystals formed from ec-LLS. The third thrust focuses on understanding and controlling ec-LLS processes for tailored III-V (GaAs, InAs, GaSb, InSb) nanoparticles and nanowires.