等价离子取代ZnO多元合金的电子能带调控及其N掺杂行为研究

ZnO的能带工程及其p型掺杂是实现其在光电器件应用的两个必要条件。本项目将ZnO合金的能带工程与ZnO的p型掺杂结合起来。提出采用等价阴阳离子复合取代形成ZnMgOS四元合金，以实现对ZnO能带结构更自由调控和更大范围的裁剪；同时，通过阴（阳）离子单独和复合协同改性来有效调控ZnO合金的电子能带结构，使其有利于N的p型掺杂。采用PLD法，以ZnS（ZnMgO）陶瓷为靶材，NO、NO2等为反应气体，结合理论模拟优化工艺，制备高质量的外延ZnOS:N、ZnMgO:N、ZnMgOS:N薄膜。研究S、Mg、S+Mg取代对于ZnOS、ZnMgO、ZnMgOS合金能带结构，特别是局域价带顶（VBM）调制的微观机制，探索S、Mg、S+Mg含量对相应合金价带弯曲和N受主能级的调控规律，实现N对ZnO多元合金高效稳定的p型掺杂，为ZnO的能带工程和p型掺杂研究提供新的思路和数据。

Bandgap engineering and p-type doping of ZnO are two key requirements towards developing ZnO-based optoelectronic devices. This project takes a joint consideration of the bandgap engineering of ZnO alloys with the p-type doping of ZnO. It proposes to form ZnMgOS quaternary alloy by a simultaneous partial replacement of anions and cations, in order to be able to tune and tailor the electronic band structure of ZnO alloys more freely and to a larger extent. Additionally, it is proposed to alter delicately the electronic band structure of ZnO alloys via either anions (cations) substitution alone, or a joint substitution of anions and cations, to make it easy to p-type doping the alloys with N. Via a systematical optimization of the deposition process complemented with theoretical modeling, high-quality epitaxial ZnOS:N, ZnMgO:N, ZnMgOS:N films are expected to be grown by pulsed laser deposition (PLD) using ZnS (ZnMgO) ceramic target and NO, NO2, etc. as reactive gas. The mechanism responsible for tuning the band structure, particularly the local valence band maximum of ZnOS, ZnMgO and ZnMgOS alloys is to be investigated, and the quantitative relationship between the contents of S, Mg, S plus Mg, and the valence band bending as well as the energy level of N acceptors of the corresponding alloys is to be explored. Realization of highly efficient and stable p-type conduction by N doping is finally expected based on these studies, contributing new ideas and data to the study of p-type doping as well as bandgap engineering of ZnO.