The fabrication of a self-powered CuInS2/TiO2 heterojunction photodetector and its application in visible light communication with ultraviolet light encryption

Abstract

A photodetector (PD) with high performance and stability in a broad range of wavelengths is essential for the broadband application in sensing, communication, and imaging. The heterojunction PDs based on CuInS₂ (CIS) nanoflakes (NFs) and TiO₂ nanorod arrays (NRs) were fabricated by a solvothermal method, and demonstrated a wide spectral response range from ultraviolet (UV) to visible without external bias. The enhanced responsivity (R), detectivity (D*), light sensitivity, linear dynamic range (LDR) and response time for the self-powered CIS/TiO₂ PD is 44.8 mA W⁻¹, 1.3 × 10¹² Jones, 2.7 × 10⁴, 88.5 dB and 2 ms by regulating the growth process of CIS NFs in the precursor solution. The excellent dual-band detection ability in the UV and visible light demonstrates the practical application feasibility and practicability of the self-powered PD in the “OR” gate of light-controlled digital logic circuit and encrypted VLC applications.