Laser ablation fabrication of a p -NiO/ n -Si heterojunction for broadband and self-powered UV–Visible–NIR photodetection

Abstract We report on the optoelectronic characteristics of p -NiO/ n -Si heterojunction photodiode for broadband photodetection, fabricated by depositing a p -type NiO thin film onto a commercial n -type silicon substrate using pulsed laser deposition (PLD) technique. The structural properties of the PLD-grown p -NiO material were analysed by means of x-ray diffraction and x-ray photoelectron spectroscopy, confirming its crystalline nature and revealing the presence of Ni vacancies, respectively. Hall measurements confirmed the p -type semiconducting nature of the NiO thin film having a carrier concentration of 8.4 × 10 16 cm −3 . The current–voltage ( I–V ) characteristics of the p -NiO/ n -Si heterojunction photodevice were investigated under different wavelengths ranging from UV to NIR. The self-bias properties under different illuminations of light were also explored systematically. Under self-bias condition, the photodiode exhibits excellent responsivities of 12.5 mA W −1 , 24.6 mA W −1 and 30.8 mA W −1 with illumination under 365 nm, 485 nm, and 850 nm light, respectively. In addition, the time dependency of the photoresponse of the fabricated photodevice has also been investigated and discussed thoroughly.