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.

Three-Dimensional (3D) Device Architectures Enabled by Oxidative Chemical Vapor Deposition (oCVD)

“…Hybrid nanostructured photodetectors have been demonstrated using oCVD PEDOT. 13 Photodetectors are essential for a wide range of applications including night vision, motion tracking, and bio-sensing. Photons are readily captured by a nanostructured form of silicon known as black silicon (b-Si).…”

oCVD PEDOT-Cl Thin Film Fabricated by SbCl5 Oxidant as the Hole Transport Layer to Enhance the Perovskite Solar Cell Device Stability

“…The selection of an appropriate oxidant in the oCVD method is of great importance as it profoundly influences the film characteristics and overall performance of the deposited material. ,− The presence of the oxidant vapor drives the polymerization process and enables in situ doping. In the oCVD process, the oxidant can be supplied through the sublimation of a solid, such as iron chloride (FeCl 3 ), − or via the vaporization of a liquid, such as vanadium oxytrichloride (VOCl 3 ) ,,,, and antimony pentachloride (SbCl 5 ). − Employing solid oxidants in the oCVD process necessitates subsequent acidic rinsing steps to remove residual byproducts generated during deposition. Conversely, the use of liquid oxidants tends to produce volatile reaction byproducts that can readily desorb from the surface during oCVD.…”

Enhanced doping and structure relaxation of unsubstituted polythiophene through oxidative chemical vapor deposition and mild plasma treatment

“…Recent rapid advancements in wearable, flexible, and portable electronics increase attention in π-conjugated polymers due to their mechanical flexibility, electrical conductivity, and tunable functionalities such as surface properties, selective permeability, and stimuli responses [1][2][3][4]. Thus far, the majority of the studies regarding conjugated polymers have focused on substituted polymers to enhance the chemical reactivity and hence facilitate solution-based polymerization processing [5][6][7].…”