In contrast to the majority of two-dimensional semiconductors such as transition metal dichalcogenides, indium selenide (InSe) possesses an intrinsic large out-of-plane oriented band-edge luminescent dipole. This unique anisotropic feature of band-edge optical emissions can be exploited to achieve enhanced optical signal in bent regions of materials created by geometrical modification. We herein investigate based on first-principle calculations the mechanism of this optical emission enhancement by modelling the photoluminescence processes in bent and flat regions of the InSe thin film. We propose in our model that the shorter-wavelength interband transition, labelled as transition B′, between the second-highest valence band and the bottom of conduction band plays an important role in the enhancing process. Our model robustly describes the dependence of optical emission enhancement in the bent InSe thin films on thickness, incident light orientation, and excitation photon energy. In particular, we found that when excitation photon energy is lower than the energy of transition B′, strong enhancement up to hundreds of times can be obtained by applying an incident light at an angle less than 70° to the InSe layers. Our results provide useful references for modulating luminescent properties of InSe films toward flexible optoelectronic device applications.

与大多数二维半导体（例如过渡金属二卤化氢）相反，硒化铟（InSe）具有固有的大的面外取向的带边发光偶极子。可以利用带边缘光发射的这种独特的各向异性特征，在通过几何修改创建的材料的弯曲区域中实现增强的光信号。我们在此基于第一原理计算，通过对InSe薄膜的弯曲和平坦区域中的光致发光过程进行建模来研究这种光发射增强的机理。我们在模型中建议将较短波长的带间跃迁标记为跃迁B'，第二价价带和导带底部之间在增强过程中起着重要作用。我们的模型有力地描述了弯曲的InSe薄膜中光发射增强对厚度，入射光方向和激发光子能量的依赖性。特别地，我们发现，当激发光子能量低于跃迁B '的能量时，通过以小于70°的角度向InSe层施加入射光，可以获得高达数百倍的强增强。我们的结果为调节InSe薄膜的发光特性向柔性光电器件应用提供了有用的参考。