Integration of MoS2 with InAlAs/InGaAs Heterojunction for Dual Color Detection in Both Visible and Near-Infrared Bands

At present, dual-channel or even multi-channel recording is a developing trend in the field of photodetection, which is widely applied in environment protection, security, and space science and technology. This paper proposes a novel MoS2/InAlAs/InGaAs n-i-n heterojunction phototransistor by integrating multi-layered MoS2 with InGaAs-based high electron mobility transistors (InGaAs-HEMTs). Due to the internal photocurrent amplification in the InGaAs channels with a narrow energy bandgap of 0.79 eV, this device exhibits high photoresponsivity (R) of over 8 x 10(5) A W-1 under near-infrared illumination of 1550 nm at 500 pW. Furthermore, with the combination of the photoconductance effect in the vertical MoS2/InAlAs/InGaAs n-i-n heterojunction and the photogating effect in the lateral phototransistor, this device possesses a unique characteristic under visible illumination that its photoresponsivity can be tuned by the top gate electrode from 6 x 10(5) A W-1 to -4 x 10(5) A W-1 by gate voltage. This may lead to a new application as an optically controlled electronic inverter, which needs further study in depth. This MoS2/InAlAs/InGaAs phototransistor builds up a new bridge between 2D materials and conventional ternary compounded semiconductor devices.