Photosensing effect of indium-doped ZnO thin films and its heterostructure with silicon

Abstract

Indium-doped zinc oxide (ZnO) thin films were coated onto glass and silicon substrates at different indium concentrations (0%, 2.5%, 5%, and 7%) using successive ionic layer adsorption and reaction (SILAR) method. Furthermore, crystalline structural, morphological, and elemental properties of indium-doped ZnO thin films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and EDAX techniques. Moreover, the optical properties were analyzed using UV-vis optical absorption, photoluminescence (PL), and Raman spectroscopy techniques. XRD analysis confirmed the growth of ZnO films with perfect inclusion of indium ions into the ZnO lattice of the hexagonal wurtzite structure. Moreover, the optical studies showed improved transmittance and band gap with the indium doping of up to 2.5%. The photosensor fabricated using the ZnO film doped with 2.5% indium concentration exhibited maximum response regarding sensing properties. A p-n heterojunction device fabricated by coating the 2.5% indium-doped ZnO on p-Si substrate showed good rectifying property with photovoltaic nature, and it responded well for UV region.