通过晶格失配调节有盖层张应变Ge量子点的光电特性  

Tuning the Optoelectronic Properties of Capped Tensile-strained Ge Quantum Dots by Lattice Mismatch

作　　者：陈其苗 宋禹忻[1] 张振普[1] 刘娟娟 芦鹏飞 李耀耀[1] 王庶民[1,4] 龚谦[1] CHEN Qimiao;SONG Yuxin;ZHANG Zhenpu;LIU Juanjuan;LU Pengfei;LI Yaoyao;WANG Shumin;GONG Qian(State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and Information Technology,CAS,Shanghai 200050;University of Chinese Academy of Sciences,Beijing 100049;State Key Laboratory of Information Photonics and Optical Communications of Ministry of Education,Beijing University of Posts and Telecommunications,Beijing 100089;Department of Microtechnology and Nanoscience,Chalmers University of Technology,Gothenburg,Sweden)

机构地区：[1]中国科学院上海微系统与信息技术研究所,信息功能材料国家重点实验室,上海200050 [2]中国科学院大学,北京100049 [3]北京邮电大学信息光子学与光通信研究院,信息光子学与光通信国家重点实验室,北京100089 [4]查尔姆斯理工大学,微技术和纳米科学系,瑞典哥德堡

出　　处：《材料导报》2018年第6期1004-1009,共6页Materials Reports

基　　金：国家自然科学基金(61404153);国家自然科学基金重点项目(61334004);国家自然科学基金创新研究组项目(61321492);上海浦江人才计划(14PJ1410600);国家重点基础研究发展规划(973计划)(2014CB643902);中国科学院战略性先导专项(XDA5-1);中国科学院重点项目(KGZD-EW-804);中国科学院高迁移率材料工程国际合作与创新项目;信息功能材料重点实验室开放项目

摘　　要：利用Ge与不同衬底形成的不同晶格失配度来调节有盖层的张应变Ge量子点的光电特性。通过有限元方法模拟并获得张应变Ge量子点内的应变分布,而后通过形变势理论和有效质量近似计算得到量子点的电子结构。与无盖层张应变Ge量子点相比,有盖层Ge量子点能保持更大的应变量。另外,随着量子点尺寸和晶格失配度的增大,导带Γ谷与导带L谷的能量差缩减,最终使Ge转变为直接带隙材料。直接带隙能量随着量子点尺寸的增大而减小。该研究结果表明张应变Ge量子点是制备包含激光器在内的Si基光源的理想材料,在未来光电子应用中有巨大潜力。The optoelectronic properties of capped tensile-strained Ge quantum dot(QD)was studied with different lattice mismatch,which was formed by Ge and various substrate.The strain distribution of Ge QDs were simulated with the aid of finite element method(FEM)and the electronic structures of capped tensile-strained Ge QDs under such strain was calculated via deformation potential theory and effective mass approach(EMA).The size effect of Ge QDs was also considered.It was found that the capped QDs hold larger strain than the uncapped ones.In addition,the energy difference betweenΓand L conduction valley reduced with the increase of the QD size and the lattice mismatch,thus converting the Ge QDs into the direct band gap material.The energy of the direct band gap decreased with the increase of the QDs’size.This work shows that the tensile-strained Ge QD is a promising light emission material for future optoelectronic applications such as lasers on Si.

关 键 词：张应变Ge 量子点 有限元 有效质量法 直接带隙 

分 类 号：O472[理学—半导体物理]