Influence of the distance between nozzle and substrate on the structural, photoluminescence, and detector characteristics of p-NiO/n-Si hetero-junction deposited by spray pyrolysis method

Abstract

In the present investigation, p-NiO has been deposited on n-Si (100) substrate by the spray pyrolysis method. The effect of the distance between the substrate and the nozzle on the structural, photoluminescence, and detection properties has been well inspected. XRD analysis proved the polycrystalline system with a cubic structure for NiO. The elemental analysis con rmed the existence of Ni, O, and Si materials without any impurities. The FESEM analysis showed nano and micro particles distributed on the Si layer, the micro particles have porous like structures which play a signi cant role as photons guider. The photoluminescence measurement depicted three main peaks at the UV and visible regions of the electromagnetic spectrum which are related to near band edge emission and defects within the crystal, respectively. I-V characteristics revealed good conductivity under UV illumination, and the highest current was recorded by a sample when the distance between the nozzle and the substrate is 25 cm. The responsivity elucidated a high value at UV region with 6.5 mA/W, and the current-time properties demonstrated good reproducibility, high stability and photoresponse, and rapid response and recovery times of 0.375 and 0.791 s, respectively at a lower bias voltage of 1.5 Volt under UV photons source.