Cu₂ZnGeS₄ is a promising semiconductor that has potentially wide applications. Intrinsic stability and electronic properties of the Cu₂ZnGeS₄ surface are investigated in this work. The surfaces are stabilized by defects that are found to show diverse physics from that of the bulk. Under Cu-rich conditions, the acceptor-like Cu-enriched and Zn-deficient defects dominate both in the bulk and on the surface. However, under Cu-poor conditions, acceptor-like Cu-deficient defects dominate in the bulk, whereas donor-like Cu-deficient and Zn-enriched defects dominate on the surface. Therefore, an n-p type inversion occurs at the area between the bulk and surface. Moreover, among the possible surface con

figurations, only the 2Zn_Cu (\(\overline{112}\)) surface does not generate surface states in the band gap. Hence, the Cu-poor condition is proposed if Cu₂ZnGeS₄ acts as a solar cell material. The results can also be generalized to other quaternary chalcogenides.

Cu ₂ ZnGeS ₄是一种具有潜在广泛应用前景的半导体。_{在这项工作中研究了Cu 2} ZnGeS ₄表面的本征稳定性和电子特性。表面被发现显示出与大块不同的物理特性的缺陷所稳定。在富铜条件下，受主状富铜和缺锌缺陷在主体和表面上均占主导地位。然而，在贫铜条件下，受主状的缺铜缺陷在体块中占主导地位，而施主状的缺铜和富锌缺陷在表面上占主导地位。因此，在体和表面之间的区域会发生np型反转。此外，在可能的表面骗局中

如图所示，只有 2Zn _Cu ( \(\overline{112}\) ) 表面不会在带隙中产生表面态。_{因此，如果Cu 2} ZnGeS ₄用作太阳能电池材料，则提出了Cu贫乏条件。结果也可以推广到其他季硫属元素化物。