High Performance and Bendable Few-Layered InSe Photodetectors with Broad Spectral Response

TLDR

Two‑dimensional crystals offer exotic dimensional‑dependent properties that make them promising for next‑generation ultrathin, flexible optoelectronic devices. The study aims to show that few‑layer InSe can serve as a versatile component for flexible optoelectronics and 2D heterostructure devices. Few‑layer InSe photodetectors on SiO₂/Si and flexible PET achieve broadband detection (450–785 nm) with peak responsivities of 12.3 A W⁻¹ and 3.9 A W⁻¹, outperforming other 2D photodetectors, and exhibit ~50 ms response, long‑term stability, and comparable performance on flexible substrates with or without bending.

Abstract

Two-dimensional crystals with a wealth of exotic dimensional-dependent properties are promising candidates for next-generation ultrathin and flexible optoelectronic devices. For the first time, we demonstrate that few-layered InSe photodetectors, fabricated on both a rigid SiO2/Si substrate and a flexible polyethylene terephthalate (PET) film, are capable of conducting broadband photodetection from the visible to near-infrared region (450–785 nm) with high photoresponsivities of up to 12.3 AW–1 at 450 nm (on SiO2/Si) and 3.9 AW–1 at 633 nm (on PET). These photoresponsivities are superior to those of other recently reported two-dimensional (2D) crystal-based (graphene, MoS2, GaS, and GaSe) photodetectors. The InSe devices fabricated on rigid SiO2/Si substrates possess a response time of ∼50 ms and exhibit long-term stability in photoswitching. These InSe devices can also operate on a flexible substrate with or without bending and reveal comparable performance to those devices on SiO2/Si. With these excellent optoelectronic merits, we envision that the nanoscale InSe layers will not only find applications in flexible optoelectronics but also act as an active component to configure versatile 2D heterostructure devices.