GaSe/MoS<sub>2</sub> Heterostructure with Ohmic‐Contact Electrodes for Fast, Broadband Photoresponse, and Self‐Driven Photodetectors
Zhenbei He, Junxiong Guo, Shangdong Li, Zhicheng Lei, Lin Lin, Yizhen Ke, Wenjing Jie, Tianxun Gong, Yuan Lin, Tiedong Cheng, Wen Huang, Xiaosheng Zhang
Abstract
Abstract In this letter, the vertically‐stacked GaSe/MoS 2 heterostructures with indium tin oxide (ITO) and Ni/Au as contact electrodes are successfully fabricated, respectively. The GaSe/MoS 2 heterostructure exhibits a broadband photoresponse covering the range of visible to near‐infrared spectra at room temperature without external bias voltage. When ITO serves as contact electrodes, a high rectification ratio, i.e., 1.5 × 10 4 at V DS = ±1 V, and an excellent photoelectric performance, i.e., responsivity of ≈0.67 A W ‐1 , specific detectivity of ≈2.3 × 10 11 cm Hz 1/2 W ‐1 and external quantum efficiency of ≈160% at the wavelength of 520 nm is achieved. Moreover, the GaSe/MoS 2 heterostructure with Ohmic‐contact ITO electrodes demonstrates a faster response time of 155 µs, which is 4 times faster than the GaSe/MoS 2 heterostructure with Ni/Au electrodes and about 300 times faster than previous reports. These results reveal the presence of an abrupt p–n junction between GaSe and MoS 2 and significant role of electrode‐contact mode in determining the photoelectric properties of GaSe/MoS 2 heterostructure.