Polarization photovoltaic effect is a unique character for an energy material with specific in‐plane anisotropy. Especially, if the energy material has a direct bandgap close to 1.6 eV, it will efficiently absorb full sunlight spectrum with specific axial polarization. In this study, polarized microtransmittance measurements of GeS multilayer with polarization angles ranging from θ = 0° (E || a) [through 90° (E || b)] to θ = 180° (E || a) have been studied near band edge. The polarized absorption edge follows a sinusoidal variation of E(θ) = 1.6 + 0.05⋅|sin(θ)| eV with respect to the angle change of the polarized absorption spectra. This anisotropic optical response is well reproduced by first‐principles calculations based on a combined Green's function technique, the GW–Bethe–Salpeter equation (BSE) approach. To characterize highly anisotropic band structure of layered GeS, polarized thermoreflectance measurement and first‐principles quasiparticle band‐structure calculations are also carried out. The interband transitions belonging to E ||a and E ||b polarizations are respectively identified. The polarized surface photovoltaic effects of a GeS Schottky solar cell are also tested. The special in‐plane optical anisotropy (along a and perpendicular to the a axis) renders GeS owning highly bi‐axial responsivity with respect to the c‐plane photoelectric conversion.

中文翻译：

---

分层GeS中的偏振光电转换

极化光伏效应是具有特定面内各向异性的能量材料的独特特征。特别是，如果能量材料的直接带隙接近1.6 eV，它将有效地吸收具有特定轴向极化的完整太阳光谱。在这项研究中，研究了极化角从θ= 0°（E || a）[至90°（E || b）]到θ= 180°（E || a）的GeS多层膜的偏振微透射率测量。乐队边缘附近。极化吸收边缘遵循E的正弦变化（θ）= 1.6 +0.05⋅| sin（θ）| eV关于极化吸收光谱的角度变化。这种各向异性的光学响应可以很好地通过基于格林函数技术，GW–Bethe–Salpeter方程（BSE）方法的第一性原理计算得到很好的再现。为了表征层状GeS的高各向异性能带结构，还进行了偏振热反射率测量和第一性原理准粒子能带结构计算。属于E ||的带间转换 a和E || b极化分别被识别。还测试了GeS肖特基太阳能电池的极化表面光伏效应。特殊的面内的光学各向异性（沿一个且垂直于a轴）使GeS相对于c平面光电转换具有很高的双轴响应度。