Interface‐Induced High Responsivity in Hybrid Graphene/GaAs Photodetector

Abstract

Photodetectors based on two‐dimensional (2D)/ three‐dimensional (3D) semiconductor heterojunction structures are emerging as appealing candidates for high‐sensitivity applications. The performances of these hybrid photodetectors are closely correlated with their current gain mechanism. Carrier recirculation is the most commonly reported mechanism. Recently, a Fermi level alignment mechanism was proposed for 2D graphene/0‐dimensional (0D) quantum dot heterostructures because of the easy Fermi level tunability of the quantum dot. In this article, an interface‐induced gain mechanism using this Fermi level alignment process is proposed and identified based on a 2D graphene/3D GaAs hybrid structure with comparative measurement configurations. Because of the high surface state density of GaAs, the photo‐excited holes tend to become trapped at the graphene/GaAs interface, which can easily lower the interface Fermi level and the Fermi level in graphene via an alignment process. When combined with the high carrier mobility characteristics of graphene, a maximum current gain of 2520 and responsivity of 1321 A W−1 are achieved in the devices. This study clarifies the role of the interface states in the gain characteristics of some 2D/3D hybrid devices, with results that are instructive for optimal device design.

High-Performance Broad-Band Photodetection Based on Graphene–MoS2xSe2(1–x) Alloy Engineered Phototransistors

“…Here, the illuminated light is absorbed by the TMDC alloy and subsequently the electron-hole pairs are generated, as shown in the Figure 3f. The photogenerated holes are then transferred to the graphene channel due to the upward band bending producing a strong photoresponse as discussed earlier 41,42 .…”

Interface Engineering Ti3C2 MXene/Silicon Self‐Powered Photodetectors with High Responsivity and Detectivity for Weak Light Applications

“…vdW heterostructures to construct Schottky barrier junction photodiodes. [9][10][11][12][13] In this type of photodiodes, the bulk semiconductors absorb photons to generate electron-hole pairs, and the 2DMs act as transparent Schottky electrodes to collect the photoinduced carriers. The photoexcited electron-hole pairs are immediately and efficiently separated by the built-in electric field at the adjacent interface between 2DMs and the underlying semiconductors, resulting in photocurrent as a function of incident light power.…”

Enhancing Performance of GaAs Photodiodes via Monolithic Integration of Self‐Formed Graphene Quantum Dots and Antireflection Surface Texturing

“…[ 42 ] The non‐catalytic behavior of graphene on GaAs could be attributed to the three orders of magnitude higher surface states density of GaAs compared with Si, leading to the electrochemically generated holes being captured at the graphene/GaAs interface. [ 43 ] In addition, graphene has been shown to be a poor electrocatalyst when it is in pristine condition, [ 44 ] which might also prevent the graphene‐catalyzed etching process to be observed on GaAs.…”