Catalyst-free growth of dense γ-In₂Se₃ nanosheet arrays and their application in photoelectric detectors

In this work, a dense γ-In₂Se₃ nanosheet array has been fabricated using the chemical vapor deposition method under atmospheric pressure. Compared with crystal silicon, the photodetector based on the γ-In₂Se₃/p-Si heterojunction exhibits a high responsivity (96.7 mA W⁻¹) at the near-infrared region, a presentable current on/off ratio (∼1000) and excellent detectivity (2.03 × 10¹² jones). Simultaneously, the obtained photodetector demonstrated a fast response speed (0.15 ms/0.5 ms) and a broadband sensitive wavelength from ultraviolet (340 nm) to near-infrared (1020 nm). The photoelectric experimental data of the device shows that its high performance is attributed to the high–light absorption capacity of the material, the rational energy band structures of γ-In₂Se₃ and p-Si, and the effective separation of photo-generated carriers caused by the formed type-II heterojunction. Our work provides the primary experimental basis for the photodetection application of the γ-In₂Se₃ nanostructure. (paper)