The Fabrication of Self-Powered CuInS2/TiO2 Heterojunction Photodetector and the Application in Visible Light Communication with Ultraviolet Light Encryption

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.