Defects properties and vacancy diffusion in Cu_(2)MgSnS_(4)  

作　　者：Kin Fai Tse Shengyuan Wang Man Hoi Wong Junyi Zhu 

机构地区：[1]Department of Physics,The Chinese University of Hong Kong,Hong Kong,China

出　　处：《Journal of Semiconductors》2022年第2期47-53,共7页半导体学报（英文版）

基　　金：support from Research Grants Council of Hong Kong(under GRF/14319416,GRF/14301318,and Direct Grant)。

摘　　要：Cu_(2)Mg_(Sn)S_(4)(CZTS)is a promising photovoltaic absorber material,however,efficiency is largely hindered by potential fluctuation and a band tailing problem due to the abundance of defect complexes and low formation energy of an intrinsic Cu_(Zn)defect.Alternatives to CZTS by group I,II,or IV element replacement to circumvent this challenge has grown research in-terest.In this work,using a hybrid(HSE06)functional,we demonstrated the qualitative similarity of defect thermodynamics and electronic properties in Cu_(2)Mg_(Sn)S_(4)(CMTS)to CZTS.We show Sn_(Mg)to be abundant when in Sn-and Cu-rich condition,which can be detrimental,while defect properties are largely similar to CZTS in Sn-and Cu-poor.Under Sn-and Cu-poor chemic-al potential,there is a general increase in formation energy in most defects except Sn_(Mg),Cu_(Mg)remains as the main contribu-tion to p-type carriers,and Sn_(Mg)may be detrimental because of a deep defect level in the mid gap and the possibility of form-ing defect complex Sn_(Mg)+Mg_(Sn).Vacancy diffusion is studied using generalized gradient approximation,and we find similar va-cancy diffusion properties for Cu vacancy and lower diffusion barrier for Mg vacancy,which may reduce possible Cu-Mg dis-order in CMTS.These findings further confirm the feasibility of CMTS as an alternative absorber material to CZTS and suggest the possibility for tuning defect properties of CZTS,which is crucial for high photovoltaic performance.

关 键 词：CMTS CZTS DEFECT hybrid functional DIFFUSION 

分 类 号：TB34[一般工业技术—材料科学与工程]