非四面体Ⅰ_(2)-Ⅱ-Ⅳ-Ⅵ_(4)四元半导体:晶体结构和电子结构  

Non-tetrahedral Ⅰ_(2)-Ⅱ-Ⅳ-Ⅵ_(4) quaternary semiconductors:Crystal structure and electronic structure

作　　者：蔡增华 赵润 CAI Zenghua;ZHAO Run(School of Physical Science and Technology,SUST,Suzhou 215009,China)

机构地区：[1]苏州科技大学物理科学与技术学院,江苏苏州215009

出　　处：《苏州科技大学学报(自然科学版)》2025年第1期31-40,共10页Journal of Suzhou University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金项目(12374090,12304110)。

摘　　要：传统的四元硫化物半导体如Cu_(2)ZnSnS_(4)和Cu_(2)ZnSnSe_(4)主要呈现四面体结构,它们已经在薄膜太阳能电池应用中展现出巨大潜力。最近,一些新的四元硫化物呈现出非四面体结构,如三角的Cu_(2)BaSnS_(4)和正交的Cu_(2)BaSnSe_(4)。由于它们展现出比传统四元半导体更为优越的光伏性能,因此备受关注。基于第一性原理计算方法,本文研究了一些非传统的四元硫化物半导体Ⅰ_(2)-Ⅱ-SnS_(4)(Ⅰ=Cu,Ag;Ⅱ=Zn,Cd,Hg,Mg,Ca,Sr,Ba)和Cu_(2)-Ⅱ-SnSe_(4)(Ⅱ=Mg,Ca,Sr,Ba)的晶体结构、电子和光学性质。通过能量相对稳定性的分析,发现了这些四元硫化物最稳定结构的一般变化趋势,即随着Ⅱ族阳离子原子大小的增加,它们的最稳定结构从传统四面体结构变为非传统的三角或正交结构。电子和光学性质的计算结果显示,大多数非传统结构的四元硫化物具有优异的带隙值(1.1~1.6 eV)和较大的可见光吸收系数(10^(4)cm^(-1))。根据Shockly-Queisser极限,大多数四元硫化物半导体具有28%左右的理论极限效率。值得注意的是,对于具有较大Ⅱ族阳离子(如Sr和Ba)的四元半导体,它们倾向于呈现三角或正交结构。由于这两种结构之间的能量差异相对较小,而电子性质的差异相对较大(从间接的1.27 eV(三角)到直接的1.64 eV(正交),如Cu_(2)BaSn Se_(4)),研究发现,这些非传统四元硫化物在单一结构中的均匀合成可能是影响其在光伏或光电化学应用中性能的关键因素之一。Conventional quaternary chalcogenides such as Cu_(2)ZnSnS_(4) and Cu_(2)ZnSnSe_(4) crystallize in tetrahedral structure(such as kesterite or stannite)and have exhibited promising potential in thin film solar cells.Recently,some new quaternary chalcogenides crystallizing in unconventional structures such as trigonal Cu_(2)BaSnS_(4) and orthorhombic Cu_(2)BaSnSe_(4) have received increasing attention for their superior photovoltaic properties and potential optoelectronic applications compared to conventional ones.Based on the first-principles calculation method,we investigated the structure,electronicand optical properties of some unconventional quaternary chalcogenide semiconductors Ⅰ_(2)-Ⅱ-SnS_(4)(Ⅰ=Cu,Ag;Ⅱ=Zn,Cd,Hg,Mg,Ca,Sr,Ba)and Cu_(2)-Ⅱ-SnSe_(4)(Ⅱ=Mg,Ca,Sr,Ba).Through the analysis of relative stability of energy,the generally variational trend of the most stable structure of these quaternary chalcogenides has been discovered.Their most stable structures change from conventional to unconventional structures with the increase of the atomic size of group Ⅱ cations.The results of electronic and optical properties show that most of these quaternary chalcogenides crystallized in unconventional structures have excellent band gap values(1.1~1.6 eV)and strong absorption of visible light.According to Shockly-Queisser limit,most of the quaternary chalcogenides have the efficiency limit around 28%.It is worth noting that quaternary semiconductors with larger group Ⅱ cations(such as Sr and Ba)tend to crystallize in trigonal or orthorhombic structure.Since the relatively small energy difference and the relatively big difference of electronic properties(from indirect 1.27 eV(trigonal)to direct 1.64 eV(orthorhombic)based on Cu_(2)BaSnSe_(4))between these two structures,we propose that uniform synthesis of these unconventional quaternary semiconductors crystallized in single structure could be one of the critical factors affecting their performance in the photovoltaic or photoelectrochemical applications.

关 键 词：四元半导体 非四面体 电子结构 

分 类 号：O469[理学—凝聚态物理]