The photogalvanic effect (PGE) occurring in noncentrosymmetric materials enables the generation of a dc photocurrent at zero bias with a high polarization sensitivity, which makes it very attractive in photodetection. However, the magnitude of the PGE photocurrent is usually small, leading to a low photoresponsivity, and therefore hampers its practical application in photodetection. Here, we propose an approach to largely enhancing the PGE photocurrent by applying an inhomogenous mechanical stretch, based on quantum transport simulations. We model a two-dimensional photodetector consisting of the wide-bandgap MgCl₂/ZnBr₂ vertical van der Waals heterojunction with the noncentrosymmetric C_3v symmetry. Polarization-sensitive PGE photocurrent is generated under the vertical illumination of linearly polarized light. By applying inhomogenous mechanical stretch on the lattice, the photocurrent can be largely increased by up to 3 orders of magnitude due to the significantly increased device asymmetry. Our results propose an effective way to enhance the PGE by inhomogenous mechanical strain, showing the potential of the MgCl₂/ZnBr₂ vertical heterojunction in the low-power UV photodetection.

发生在非中心对称材料中的光电效应 (PGE) 能够在零偏压下产生具有高偏振灵敏度的直流光电流，这使其在光电检测中非常有吸引力。然而，PGE 光电流的幅度通常很小，导致光响应性低，因此阻碍了其在光电检测中的实际应用。在这里，我们提出了一种基于量子传输模拟通过应用非均匀机械拉伸来大大增强 PGE 光电流的方法。我们模拟了一个二维光电探测器，它由宽带隙 MgCl ₂ /ZnBr ₂垂直范德华异质结和非中心对称C _{3 v 组成}对称。偏振敏感的 PGE 光电流是在线性偏振光的垂直照射下产生的。通过在晶格上应用非均匀机械拉伸，由于器件的不对称性显着增加，光电流可以大大增加多达 3 个数量级。我们的结果提出了一种通过不均匀机械应变增强 PGE 的有效方法，显示了 MgCl ₂ /ZnBr ₂垂直异质结在低功率紫外光电检测中的潜力。