Hybrid Silicon-Polymer Photodetector Engineered Using Oxidative Chemical Vapor Deposition for High-Performance and Bias-Switchable Multi-Functionality

Abstract

Black silicon (b-Si) featured by anti-reflective surfaces is extensively studied to realize highly sensitive photodetectors. The key to augmenting the light-detection capability of b-Si is to facilitate charge extraction while limiting undesired recombination events at surface defects. To this end, oxidative chemical vapor deposition (oCVD) is leveraged to form a highly conformal and conductive (3000 S cm−1) organic transport layer, poly(3,4-ethylenedioxythiophene) (PEDOT), on b-Si nanostructures. The oCVD PEDOT instrumentally extracts photo-induced charges, through which b-Si photodetectors implementing oCVD PEDOT achieve a superior photo-detectivity of 1.37 × 1013 Jones. Furthermore, by engineering the pore dimension of b-Si, a mode-tunable Si photodetector is contrived, where the functions of broad-band and visible-blinded modes are switched facile by a bias polarity. The unprecedented device paves the way for extending the applications of Si detectors toward novel sensory platforms such as night-vision, motion tracking, and bio-sensing.