人工晶体学报2025，Vol.54Issue(6)：997-1004,8.DOI:10.16553/j.cnki.issn1000-985x.2025.0002
Mist-CVD法生长LiGa5O8单晶薄膜及其导电机理研究
Growth of LiGa5O8 Single Crystal Thin Films and Their Conductive Mechanism by the Mist-CVD Method
摘要
Abstract
Abstarct:The phenomenon of facile n-type doping and the challenges associated with p-type doping are frequently observed in wide-bandgap oxide semiconductors.LiGa5O8 is an innovative oxide semiconductor material which is theoreti-cally amenable to bipolar doping.Remarkable properties are exhibited by LiGa5O8,positioning it as a promising candidate in the realm of oxide semiconductor optoelectronics,with the potential to advance the development of high-performance PN homojunctions and other bipolar devices.In this study,unintentionally doped high-quality single crystal LiGa5O8 thin films were synthesized by the mist-chemical vapor deposition(mist-CVD)method,and their quality,optical and electrical properties were meticulously measured and characterized.The experimental results indicate that the synthesized LiGa5O8 thin films exhibit excellent quality and crystallinity,with a thickness of 484 nm,small surface roughness(Rq=2.48 nm,Ra=1.73 nm),and an optical bandgap of 5.22 eV,with a chemical composition ratio of Li,Ga,and O approximately 1∶5∶8.The films are characterized by n-type conductivity,with conductivity diminishing as lithium content increases,while p-type conductivity is not observed.The photodetectors prepared using the obtained LiGa5O8 thin films demonstrate favorable I-V and I-t characteristics under 254 nm illumination.Theoretical calculations of the band structure suggest that achieving p-type doping in LiGa5O8 is more challenging than n-type doping.By analyzing the intrinsic defects GaLi and LiGa in the oxygen-rich conditions of LiGa5O8,it is found that the formation energy of GaLi defects is exceptionally low,introducing shallow donor energy levels,thus resulting in the n-type conductive characteristics of the films;simultaneously,as the proportion of Li increases,GaLi defects compensate for Li acceptors,leading to negligible conductivity in the films.Future endeavors will encompass doping with elements such as Si,Ge and P,with the objective of obtaining higher carrier concentration LiGa5O8 crystal thin film materials.关键词
宽禁带氧化物半导体/LiGa5O8单晶薄膜/雾化学气相沉积法/n型导电/本征缺陷Key words
wide-bandgap oxide semiconductor/LiGa5O8 single crystal film/mist-CVD method/n-type conduction/intrinsic defect引用本文复制引用
赵昊,余博文,李琪,李光清,刘医源,林娜,李阳,穆文祥,贾志泰..Mist-CVD法生长LiGa5O8单晶薄膜及其导电机理研究[J].人工晶体学报,2025,54(6):997-1004,8.基金项目
国家自然科学基金(51932004) （51932004）
