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

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/SnS₂/HgCdTe vdWs device and a graphene/MoSe₂/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 × 10¹⁰ 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.