Facile fabrication of p-Si/κ-In2Se3 heterojunction and investigation of photodetector performance under red and blue light

κ-In2Se3 film was coated on p-Si by electron beam method. SEM, transmittance, EDS and optical absorption analyses of the film were performed. Photodetection performances of the p-Si/κ-In2Se3 device were evaluated upon various light irradiations of blue (443 nm) and red light (625 nm). A very high rectifying ratio of 3.2 × 105 was obtained in the dark (at ± 3.0 V). For 14 mW/cm2, the optimum values of ON/OFF ratio, responsivity, external quantum efficiency and specific detectivity were 469, 643 mA/W, ∼87 % and 8.21 × 1012 for red light and 597, 82.8 mA/W, ∼16 % and 1.04 × 1011 Jones for blue light, respectively. In the analysis of the response time, there was no regular change with increasing light intensity, with rise and fall times on the order of milliseconds, and these times were relatively lower in blue light than in red light. The device design and experimental results may be promising for photodetectors at different wavelengths.