Zn_(1-x)Cd_xS三元混晶的电子结构及光学性质计算与实验验证  

Calculation and Experimental Verification for Zn_(1-x)Cd_xS Ternary Mixed Crystals on Electronic Structures and Optical Properties

作　　者：李萍[1] 辛传祯[2] 徐建萍[2] 张晓松[2] 李德军[3] 李岚[2] 

机构地区：[1]天津理工大学理学院,天津300384 [2]天津理工大学材料物理研究所,天津300384 [3]天津师范大学物理与电子信息学院,天津300387

出　　处：《发光学报》2012年第7期720-728,共9页Chinese Journal of Luminescence

基　　金：国家自然科学基金(60877029);天津市自然科学基金(09JCYBJC01400)资助项目

摘　　要：基于密度泛函理论的平面波超软赝势法,计算了Zn1-xCdxS三元混晶的电子结构和光学性质。计算结果表明,Cd进入ZnS晶格后,禁带宽度变窄,硫空位(VS)缺陷能级随x值增大逐渐向费米能级移动,在紫外和可见波段的吸收截止波长随着x值增大逐渐红移。采用共沉淀法制备了Zn1-xCdxS三元混晶,XRD图谱表明形成了Zn1-xCdxS合金相,吸收光谱显示了与理论计算相符的能带和吸收截止边的移动规律,荧光光谱显示与VS相关的发射峰随x增大逐渐红移,与计算得到的VS缺陷能级的移动规律相同。The electronic structures and optical properties of Zn1-xCdxS ternary mixed crystals have been investigated using the first-principle plane-wave pseudopotential method.Comparison of calculations with different Cd doping concentration,the band gap shows gradually decrease with Cd doping concentration increasing.This band-narrowing phenomenon is ascribed to the reduction of bottom of conduction band determined by low energy electrons of Zn4s orbit and the elevation of top of valence band which was formed by the electrons of S3p states.Also the sulfur vacancy level was calculated and showed a shift near to the Fermi level with an increased of Cd doping concentration.The dielectric function and absorption coefficient of Zn1-xCdxS are also studied.For the absorption coefficient calculation of Zn1-xCdxS,we found that absorption onset in UV-Vis spectrum shifts to low energy with x increase.Moreover,the XRD,fluorescence spectrum and experimental absorption spectra of Zn1-xCdxS prepared by chemical synthesis and annealing treatment are obtained.The results exhibit agreement with the calculations.

关 键 词：密度泛函理论 电子结构 光学性质 Zn1-xCdxS三元混晶 

分 类 号：O471.6[理学—半导体物理] O472.3[理学—物理]