To develop an efficient photocatalyst with intense visible light absorption and high charge mobility is important but still remains a problem. In this work, we have explored the electronic properties of C-monodoped, C-Ge, and C-Sn codoped GaN nanosheets by the hybrid density functional theory in order to find the excellent photocatalytic materials. Results indicate the monodoping of C introduces unoccupied impurity states inside the band gap that serve on recombination centers. Thus, the C monodoping is not suitable to ameliorate visible light absorption. Moreover, the C-Ge and C-Sn codoping not only successfully reduce the band gap of nanosheet GaN but also avoid the unoccupied impurity states. The charge-compensated C-Ge and C-Sn codoped GaN nanosheets are energetically favorable for hydrogen evolution but not insufficient to produce oxygen, indicating that they could serve as Z-scheme photocatalysts. In particular, the minimum defect formation energy of C-Ge is negative and lowest. The C-Ge codoped GaN system has dynamic stability. So, the C-Ge codoped nanosheet GaN is one of the most prospective candidates for the decomposition of hydrogen from water.

开发具有强烈的可见光吸收和高电荷迁移率的有效的光催化剂是重要的，但仍然是一个问题。在这项工作中，我们通过杂化密度泛函理论探索了C-单掺杂，C-Ge和C-Sn共掺杂的GaN纳米片的电子性能，以便找到出色的光催化材料。结果表明，C的单掺杂会在能带隙内将未占据的杂质态引入复合中心。因此，C单掺杂不适合于改善可见光吸收。而且，C-Ge和C-Sn共掺杂不仅成功地减小了纳米片GaN的带隙，而且避免了未占据的杂质态。电荷补偿的C-Ge和C-Sn共掺杂的GaN纳米片在能量上有利于析氢，但不足以产生氧气，表明它们可以用作Z型光催化剂。特别地，C-Ge的最小缺陷形成能为负且最低。C-Ge共掺杂GaN系统具有动态稳定性。因此，C-Ge共掺杂纳米片GaN是从水中分解氢的最有希望的候选者之一。