Charge Sampling Photodetector Based on van der Waals Heterostructures

Abstract

Photodetector arrays are key component in image sensors. Charge-coupled devices (CCD) based photodetection is widely used due to their high resolution, large sensitivity, and low noise. However, the complex device structure, destructive and sequential readout method are primary concerns in expanding its application scenarios. Here, a charge sampling photodetector (CSP) based on fully 2D absorption/dielectric/readout van der Waals heterostructures (vdWs) is reported. Photo-charges generated in the absorption layer are stored in a potential well of the vdWs, which enables weak signal detection and imaging after the charge integration process. A stacked transistor in the readout layer then nondestructively maps out the collected charges in a random-access manner with high fill factor. With a properly engineered absorption layer, CSP can realize broadband detection from visible to mid-IR range at room temperature and low operation voltage. Our device combines the advantages of CCD and complementary metal-oxide-semiconductor image technology, which exemplifies a promising candidate for next-generation photodetectors.