High Detectivity Dual-Band Infrared Photodetectors with Dislocation-Assisted Photoconductive Gain via Hetero-Epitaxial Growth

Abstract

Multispectral infrared imaging can acquire spectral information that is not attainable from single band photodetectors. While emerging nanomaterials such as colloidal quantum dots and 2D materials are heavily studied to realize dual-band photodetectors by stacking them vertically, no device has yet demonstrated high detectivity with high response speeds. In this work, bias-tunable, two-terminal dual-band photodetectors are demonstrated that can cover short-wavelength and mid-wavelength infrared at 300 K. A metamorphic barrier is developed to connect short and mid-wave infrared back-to-back diodes while simultaneously providing photocarrier trap states for dislocation-assisted photoconductive gain for mid-infrared detection. The high specific detectivity of 3.8 × 1010 Jones and rapid response speeds of ？2 ？s are achieved in the mid-wavelength infrared channel by precise control of metamorphic barrier and absorber thickness. This device is fully compatible with readout integrated circuits, making it a promising candidate for next-generation multispectral infrared imaging.