Graphene/GaAs Schottky Junction Near-Infrared Photodetector With a MoS2 Quantum Dots Absorption Layer

MoS ₂ , as a new generation of 2-D materials after graphene, shows excellent properties and has attracted extensive attention. More importantly, it can be combined with graphene devices to improve their performance. In this work, a MoS ₂ /graphene/GaAs Schottky junction near-infrared (NIR) photodetector is investigated. A MoS ₂ quantum dot (QD) absorption layer is added on the traditional graphene/GaAs structure, and the QDs are used to enhance the absorption rate of graphene for NIR light, thereby improving the device performance. In subsequent tests, it is found that the photodetector has a responsivity of 19.9 mA/W under the 808-nm incident light at zero bias, which is much higher than that of ordinary graphene/GaAs photodetectors. Furthermore, the detection rate of the device can reach $4.86\times10$ ¹⁰ cm $\cdot $ Hz $^{1/2}\cdot \text{W}$ ⁻¹ , and the response/recovery times are 46.8 and $557 ~\mu \text{s}$ , respectively; it is also found that the response wavelengths of the device have been extended, and it has a certain response in the 1064-nm wavelength. The excellent performance of MoS ₂ /graphene/GaAs structure indicates that it has good application prospects in the field of NIR photodetectors.