Cu$_3$SbSe$_4$ is a promising thermoelectric material due to high thermopower($>400\ \mu$V/K) at 300K and higher. Although it has a simple crystal structurederived from zinc blende structure, previous work has shown that the physics ofband gap formation is quite subtle due to the importance of active lone pair(5$s^2$) of Sb and the non-local exchange interaction between these and Se 5$p$electrons. Since for any application of semiconductors understanding theproperties of defects is essential, we discuss the results of a systematicstudy of several point defects in Cu$_3$SbSe$_4$ including vacancies andsubstitutions for each of the components. First principles calculations usingdensity functional theory show that among variety of possible dopants, $p$-typedoping can be done by substituting Sb with group $IV$ elements including Sn,Ge, Pb and Ti and $n$-type doping can be done by replacing Cu by Mg, Zn. Dopingat the Se site appears to be rather difficult. Electronic structurecalculations also suggest that the $p$-type behavior seen in nominally pureCu$_3$SbSe$_4$ is most likely due to Cu vacancy rather than Se vacancy.
展开▼
机译：Cu $ _3 $ SbSe $ _4 $是一种有前途的热电材料，因为在300K或更高温度下具有较高的热功率（$> 400 \\ mu $ V / K）。尽管它具有简单的锌混和结构晶体结构，但先前的研究表明，由于Sb的活性孤对（5 $ s ^ 2 $）的重要性以及非局部交换相互作用，带隙形成的物理原理非常微妙。在这些和Se 5 $ p $电子之间。由于对于半导体的任何应用而言，了解缺陷的性质都是至关重要的，因此我们讨论了对Cu $ _3 $ SbSe $ _4 $中几个点缺陷（包括每个组件的空位和替代）进行系统研究的结果。使用密度泛函理论进行的第一性原理计算表明，在各种可能的掺杂剂中，可以用Sb替换$ IV $组元素（包括Sn，Ge，Pb和Ti）来完成$ p $型掺杂，而通过以下方法完成$ n $型掺杂：用镁，锌代替铜。在硒位点掺杂似乎很困难。电子结构计算还表明，名义上纯Cu $ _3 $ SbSe $ _4 $中出现的$ p $型行为很可能是由于Cu的空位而不是Se的空位。
展开▼
