Barrier‐Type Room‐Temperature Infrared Detector Based on 2D/3D van der Waals Heterostructures

Abstract Semiconductor heterostructures play a crucial role in optoelectronics. The interface mismatch of heterogeneous materials leads to nonideal carrier transport. In infrared detectors, the interface mismatch results in a high dark current, which leads to low sensitivity, operating temperature, and large size. Here, van der Waals (vdWs) heterogeneous integration is introduced into mercury cadmium telluride (MCT)‐based infrared detectors. Two types of vdWs barrier structure MCT‐based devices are demonstrated, including a graphene/SnS 2 /HgCdTe vdWs device and a graphene/MoSe 2 /HgCdTe vdWs device, to achieve high‐operating‐temperature (HOT) mid‐wave infrared detection. Thanks to vdWs integration, unipolar barrier structures with high‐quality interfaces are achieved, showing effective suppression of dark current at high temperatures. The dark current density of the MCT‐based vdWs detector is ≈10 −2 A cm −2 at room temperature. The MCT‐based vdWs barrier detectors have great potential for uncooled infrared detection. The detectors show a sensitive response to mid‐wave infrared irradiation with a high detectivity of 3.01 × 10 10 cm Hz 1/2 W −1 and a high external quantum efficiency of 60.9% at room temperature. The findings present a versatile strategy for fabricating a superior interface for high‐operating‐temperature infrared photodetectors with high sensitivity and small size. It makes a significant step forward in the development route of photodetectors.