摘要
研究了In液滴法生长InAs量子点时不同衬底温度,以及是否引入退火的量子点生长情况并建立了物理模型。发现In原子沉积在衬底表面会首先沿[11-0]方向形成条状量子线,由于表面能会趋于最小,量子线会分裂成小段成为量子点的核心,当衬底温度从460℃上升至480℃时,量子点增多的同时量子线减少,且纳米结构的平均高度从4.09nm上升至4.58nm。在衬底温度为480℃的条件下引入退火后,扫描区域内只存在量子点结构,纳米结构平均高度上升至8.56nm。认为In液滴法生长量子点,是一个先形成量子线,量子线再分裂形成量子点的核心,继而捕捉由ES势垒束缚在台阶边缘的原子形成量子点的过程,退火的引入会促进量子线-量子点的转化,提高尺寸均匀性,并由此建立了物理模型。
InAs quantum dots(QDs)grown by indium droplet epitaxy at different substrate temperatures,without or with annealing are reported in this work.At last,a physical model is build.Indium droplets form quantum wires(QWs)along the[11-0]direction at first,then divide into short parts to maintain the minimum surface energy,and these parts become the nuclei of quantum dots.While substrate temperature increases from460to480℃,parts coming from the quantum wires become more as well as QDs,at the same time,the number of QWs decreases,which leads to the increase of nanostructure’s average height from4.09to4.58nm.After the annealing introduced to the experiment under the condition of substrate temperature480℃,QDs are the only nanostructure in the scanning area with its average height increases to8.56nm.It can be speculated that the growth of InAs quantum dots by indium droplet epitaxy is a progress which form QWs at first,then QWs divide into short parts capturing atoms absorbed to the edge of steps because of the influence of the Ehrlich-Schwoebel barriers(ES barriers)to form QDs.Also,the introduction of annealing will promote the QW-to-QDs transformation,and improve the uniformity of QDs’size.At last,a physical model is build according to the analysis above.
作者
许筱晓
郭祥
王一
罗子江
杨晨
杨晓珊
张之桓
刘健
丁召
XU Xiaoxiao;GUO Xiang;WANG Yi;LUO Zijiang;YANG Chen;YANG Xiaoshan;ZHANG Zhihuan;LIU Jian;DING Zhao(College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China;School of Information, Guizhou University of Finance and Economics, Guiyang 550004,China)
出处
《功能材料》
EI
CAS
CSCD
北大核心
2018年第3期3203-3206,3212,共5页
Journal of Functional Materials
基金
国家自然科学基金资助项目(61564002
11664005
61604046)
关键词
量子点
液滴外延法
INAS
衬底温度
退火
物理模型
quantum dot
droplet epitaxy
InAs
substrate temperature
annealing
physical model
