Two-dimensional (2-D) materials, especially transition metal dichalcogenides (TMDCs), have attracted great attention due to their unique properties and the vast possibility they offer when combined into van der Waals heterostructures (vdWHs), for example in optoelectronic applications. Although various photodetectors based on TMDC vdWHs have been successfully synthesized, an ab initio simulation framework dedicated to such devices is still missing. In this work, we investigate two photodetector designs based on MoSe₂-WSe₂ vdWHs through a recently developed approach combining density functional theory and quantum transport calculations. Geometries with a partial and total TMDC overlap are considered, with a p-doped (n-doped) left (right) extension and an intrinsic region in the middle. We show that the partial overlap structure supports a non-zero photo-current, even without a p–n junction, and gives rise to the bulk photovoltaic effect (BPVE). The present results provide an easy-to-fabricate guideline for engineering the BPVE in the TMDC vdWHs.

二维 (2-D) 材料，尤其是过渡金属二硫属化物 (TMDC)，由于其独特的性质以及在与范德华异质结构 (vdWH) 结合时提供的巨大可能性而引起了极大的关注，例如在光电应用中。尽管已经成功合成了基于 TMDC vdWH 的各种光电探测器，但仍然缺少专门用于此类设备的从头算模拟框架。在这项工作中，我们研究了两种基于 MoSe ₂ -WSe _{2的光电探测器设计}vdWHs 通过最近开发的结合密度泛函理论和量子传输计算的方法。考虑具有部分和全部 TMDC 重叠的几何形状，其中 p 掺杂（n 掺杂）左（右）延伸和中间的本征区域。我们表明，即使没有 ap-n 结，部分重叠结构也支持非零光电流，并产生体光伏效应 (BPVE)。目前的结果为在 TMDC vdWH 中设计 BPVE 提供了一个易于制作的指南。