Liu Sijie, Xiao Wenbo, Zhong Mianzeng, Pan Longfei, Wang Xiaoting, Deng Hui-Xiong, Liu Jian, Li Jingbo, Wei Zhongming
State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100083, People's Republic of China.
Nanotechnology. 2018 May 4;29(18):184002. doi: 10.1088/1361-6528/aaafa2. Epub 2018 Feb 15.
Photodetectors with high polarization sensitivity are in great demand in advanced optical communication. Here, we demonstrate that photodetectors based on titanium trisulfide (TiS) are extremely sensitive to polarized light (from visible to the infrared), due to its reduced in-plane structural symmetry. By density functional theory calculation, TiS has a direct bandgap of 1.13 eV. The highest photoresponsivity reaches 2500 A W. What is more, in-plane optical selection caused by strong anisotropy leads to the photoresponsivity ratio for different directions of polarization that can reach 4:1. The angle-dependent photocurrents of TiS clearly display strong linear dichroism. Moreover, the Raman peak at 370 cm is also very sensitive to the polarization direction. The theoretical optical absorption of TiS is calculated by using the HSE06 hybrid functional method, in qualitative agreement with the observed experimental photoresponsivity.
具有高偏振灵敏度的光电探测器在先进光通信中需求巨大。在此，我们证明基于三硫化钛（TiS）的光电探测器对偏振光（从可见光到红外光）极其敏感，这是由于其面内结构对称性降低所致。通过密度泛函理论计算，TiS的直接带隙为1.13电子伏特。最高光响应率达到2500 A/W。此外，由强各向异性引起的面内光学选择导致不同偏振方向的光响应率之比可达4:1。TiS的角度相关光电流清晰显示出强烈的线性二色性。此外，370 cm处的拉曼峰对偏振方向也非常敏感。利用HSE06杂化泛函方法计算了TiS的理论光吸收，与观察到的实验光响应率定性一致。
