2D In₂S₃ Nanoflake Coupled with Graphene toward High‐Sensitivity and Fast‐Response Bulk‐Silicon Schottky Photodetector

Abstract

Silicon‐based electronic devices, especially graphene/Si photodetectors (Gr/Si PDs), have triggered tremendous attention due to their simple structure and flexible integration of the Schottky junction. However, due to the relatively poor light–matter interaction and mobility of silicon, these Gr/Si PDs typically suffer an inevitable compromise between photoresponsivity and response speed. Herein, a novel strategy for coupling 2D In2S3 with Gr/Si PDs is demonstrated. The introduction of the double‐heterojunction design not only strengthens the light absorption of graphene/Si but also combines the advantages of the photogating effect and photovoltaic effect, which suppresses the dark current, accelerates the separation of photogenerated carriers, and brings photoconductive gain. As a result, In2S3/graphene/Si devices present an ultrahigh photoresponsivity of 4.53 × 104 A W−1 and fast response speed less than 40 µs, simultaneously. These parameters are an order of magnitude higher than pristine Gr/Si PDs and among the best values compared with reported 2D materials/Si heterojunction PDs. Furthermore, the In2S3/graphene/Si PD expresses outstanding long‐term stability, with negligible performance degradation even after 1 month in air or 1000 cycles of operation. These findings highlight a simple and novel strategy for constructing high‐sensitivity and ultrafast Gr/Si PDs for further optoelectronic applications.

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.…”

“…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. [10] It has been reported that the graphene/Si photodiode with ultra-shallow junction possesses internal quantum efficiency approaching the upper-limit of Si based ultraviolet PDs. [14] Nevertheless, the complex transfer process for the fabrication of vdW heterojunction PDs hinders their applications for large-scale, high-integration devices.…”

Intact Vertical 3D–0D–2D Carbon‐Based p–n Junctions for Use in High‐Performance Photodetectors

“…As the 2D-Gr and 3D-Gr components have different work functions, the vertical p-n junction interface can be clearly identified in the surface potential images. The difference between the Fermi levels in the 2D-Gr and 3D-Gr layers, ΔE f , can be expressed via the following equations [30][31][32]…”

Ambipolar Plasmon‐Enhanced Photodetector Built on Germanium Nanodots Array/Graphene Hybrid

“…Scanning Kelvin probe microscopy (SKPM) is an effec tive method to explore the flow of the separated electrons and holes by measuring the surface potential difference (SPD) between graphene and Ge nanodots without and with light irradiation. [33][34][35][36] SPD is defined by the difference in the Fermi level between graphene and Ge nanodots as shown in the following: E e P eP e P f g raphene G e G e g raphene…”