Ⅱ-Ⅵ族碲化物体单晶低温光致发光谱研究（英文）  

Study on the Low Temperature Photoluminescence Spectra of Ⅱ-Ⅵ Group Telluride Bulk Crystals

作　　者：徐亚东[1] 刘航[1] 何亦辉[1] 周岩[1] 介万奇[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《光谱学与光谱分析》2015年第3期582-586,共5页Spectroscopy and Spectral Analysis

基　　金：The National Natural Science Foundations of China(51202197);the National"973"Program(2011CB610403);the Specialized Research Fund for the Doctoral Program of Higher Education of China(20116102120014);the Foundation of Institute of Nuclear Physics and Chemistry,CAEP(2011CX03)

摘　　要：采用熔体法生长Ⅱ-Ⅵ族碲化物体单晶时,不同的生长条件及热经历过程会导致生长态晶体材料中,占主导的点缺陷类型存在较大的差异,进而影响了晶体的物理性能及器件的使用。低温光致发光(PL)谱作为一种无损检测方法,可以用于研究不同条件下生长的Ⅱ-Ⅵ族碲化物体单晶中的点缺陷和杂质的能级状态。对比富Te条件下生长的未掺杂ZnTe和CdTe晶体在8.6 K下的PL谱可以发现,电阻率较低的p型ZnTe晶体,其PL谱中,电子到中性受主复合发光峰(e,A^0)强度高于施主-受主对复合发光峰(DAP),而高电阻率阻n型CdTe晶体则刚好相反,这可能是由于生长速率及降温过程的热经历不同导致占主导的本征点缺陷类型不同造成的。按化学计量比生长的未掺杂CdZnTe晶体,其PL谱中自由激子发光峰(D^0,X)占主导,而(e,A^0)峰强度高于DAP峰,变温PL谱测试表明当温度高于15 K时,(e,A^0)峰与DAP峰逐渐叠加在一起。In掺杂导致在富Te条件下生长的CdZnTe晶体的PL谱中产生明显的A中心复合发光峰,与导带的能量差约为0.15 eV,主要与In补偿Cd空位形成的复合体[In_(Cd)^+V_(Cd)^(2-)]^-有关,且其强度与In掺杂元素的含量成正比。The dominant point defects in Ⅱ-Ⅵ group telluride bulk crystals grown from melt usually varied due to different growth conditions and cooling history,in turn affect the electrical and optical behaviors of corre-sponding single crystals and devices.Low temperature photoluminescence （PL）spectra acts as a contact-less and non-destructive technique,can be used to evaluate the behaviors of point defects and impurities in the as-grown telluride bulk crystals.With the purpose of comparing the defect structures in un-doped ZnTe and CdTe crystals grown under Te-rich condition,8.6 K PL spectra were obtained.The conductivity type and resistivity were investigated by Hall-effect measurements at room temperature （RT）.For p-type low resistivity ZnTe crystal,the intensity of free electron to neutral acceptor （e,A0 ）transition is higher than the donor-acceptor pair （DAP）transition,which predominates in the PL spectra.However,in the contrary,DAP peak domi-nates the PL emissions for n-type high resistivity CdTe.This difference is mainly attributed to the distinct properties of the grown-in point defects due to different growth velocities and cooling processes.In terms of the un-doped CdZnTe crystal grown under stoichiometry,neutral donor bound exciton （D0 ,X）emission is predominated in the 9.2 K PL spectra,with the intensity of （e,A0 ）peak is higher than DAP peak,which then overlaps to each other when the temperature higher then 15 K.In the case of In-doped CdZnTe crystal grown by Te-rich situation,A-center emission is clearly observed,which introduces an energy level approxi-mately of 0.15 eV,with the intensity proportional to the concentration of indium dopant.This defect is seem-ingly related to the complex of [In＋Cd V2 -Cd ]- formed by a shallow donor InCd and Cd vacancy.

关 键 词：Ⅱ-Ⅵ族碲化物 光致发光谱 点缺陷 掺杂 

分 类 号：O74[理学—晶体学]