High-Performance Broadband Photodetectors Based on <i>n</i>-MoS<sub>2</sub>/p-Ge<sub>0.9</sub>Sn<sub>0.1</sub> Heterojunctions
Kaixiang Shu, Wei Gao, Fengshuo Wan, Shuhui Yang, Zhiying Dan, Liangwei Wu, Qixiao Zhao, Chunlai Xue, Nengjie Huo, Jingbo Li
Abstract
P–N junctions are essential building blocks for electronic and optoelectronic devices and exhibit a wide range of applications in the field of photodetectors. In this work, high-performance self-powered photodetectors with spectral coverage ranging from the visible to near-infrared rrange (405–1310 nm) has been successfully fabricated by combining a p-type Ge0.9Sn0.1 thin film with an n-type multilayered molybdenum disulfide (MoS2) into a type-II band alignment. Benefiting from the great light absorption of the multilayer MoS2 and the high in-plane mobility of the moderate Sn-doped Ge0.9Sn0.1 film with a direct band gap, the constructed P–N heterojunction can effectively generate and separate the photogenerated carriers and lead to superior zero-biased photodetection performance. The device exhibited a fast response time of 200 μs, an ultralow dark current of ∼0.1 pA and high photoswitching ratio of ∼104. In addition, the maximum values of photoresponsivity and detectivity are calculated to be 462 mA/W and 2.3 × 1012 Jones, respectively. This work provides the new promising candidates for self-powered photodetectors toward broadband, fast speed, high sensitivity, and low power consumption.