Self‐Powered UV–Near Infrared Photodetector Based on Reduced Graphene Oxide/n‐Si Vertical Heterojunction

Abstract

A novel self-powered photodetector based on reduced graphene oxide (rGO)/n-Si p-n vertical heterojunction with high sensitivity and fast response time is presented. The photodetector contains a p-n vertical heterojunction between a drop-casted rGO thin film and n-Si. Contacts between the semiconductor layer (rGO, n-Si) and source-drain Ti/Au electrodes allow efficient transfer of photogenerated charge carriers. The self-powered UV-near infrared photodetector shows high sensitivity toward a spectrum of light from 365 to 1200 nm. Under the 600 nm illumination (0.81 mW cm ), the device has a photoresponsivity of 1.52 A W , with fast response and recover time (2 ms and 3.7 ms), and the ON/OFF ratios exceed 10 when the power density reaches ≈2.5 mW cm . The high photoresponse primarily arises from the built-in electric field formed at the interface of n-Si and rGO film. The effect of rGO thickness, rGO reduction level, and layout of rGO/n-Si effective contact area on device performance are also systematically investigated.

Self‐Powered Photodetectors Based on 2D Materials

“…It exhibits excellent optical responsivity of ≈520 mA W −1 , a high optical switching ratio of over 1.5 × 10 5 , and a fast response speed of 13.9 µs at 808 nm illumination and zero bias. Li et al reported a self‐powered photodetector based on reduced graphene oxide (rGO)/Si p–n vertical heterojunction (Figure c). Under the irradiation of light with a wavelength of 600 nm, the device exhibits a photoresponsivity of 1.52 A W −1 and a fast photoresponse response rate of 2 ms at zero bias and exhibits a high light on/off ratio of 10 4 .…”

“…c) Schematic diagram of graphene oxide/n‐Si p–n vertical heterojunction. Reproduced with permission . Copyright 2016, Wiley‐VCH.…”

Enhanced Performance of a Self‐Powered Organic/Inorganic Photodetector by Pyro‐Phototronic and Piezo‐Phototronic Effects

“…In recent years, self-powered PDs have been demonstrated through integrating the PDs with external power sources such as piezoelectric and/or triboelectric nanogenerators to realize a self-powered photodetection system. [16][17][18][19][20] Compared to the integration of PDs with external power sources, the photovoltaic effect is a phenomenon naturally existed in semiconductor junction-based devices, [21] making the self-powered PDs facile-manufactured and cost-effective.Current photodetection technologies primarily rely on separate photoconductive semiconductor materials with certain band gaps corresponding to distinct spectral ranges, such as silicon for infrared light, [10,22,23] low band gap 2D semiconductors for visible light, [24][25][26] and gallium nitride (GaN) and zinc oxide (ZnO) for ultraviolet (UV) light. [16][17][18][19][20] Compared to the integration of PDs with external power sources, the photovoltaic effect is a phenomenon naturally existed in semiconductor junction-based devices, [21] making the self-powered PDs facile-manufactured and cost-effective.…”

Nanostructured Materials and Architectures for Advanced Infrared Photodetection

“…The prominent advantage of heterostructured photodetectors in that photogenerated electrons and holes could be separated directly at the interface if proper band alignment is formed. This could be realized by choosing the materials with type II band offsets . Taking the recent 2D materials as the example, Figure shows the various types of heterostructured photodetectors in literature.…”