Improved electrical carrier dynamics and UV detection performance of Zn1-xWxO nanostructured thin films

Abstract

Current work reports development of Zn1-xWxO nanostructured thin films with Tungsten (W) doping level of 0.0, 1.0, 2.5 and 5.0 wt.% onto glass substrates via successive ionic layer adsorption and reaction (SILAR) method. Films demonstrates improved carrier dynamics and UV photodetection in correlation with W doping level and their suitability in advanced optoelectronics devices. The specimen morphological and structural properties is examined via field emission scanning electron spectroscopy (FESEM) and X-ray diffraction (XRD). In order to understand the electronic structure and carrier dynamics, Raman, UV–Vis, photoluminescence (PL) and time resolve photoluminescence (TRPL) Spectroscopy were employed. Films growth reveals crystallization in hexagonal wurtzite structure and preferred orientation along (002) plane (c-axis). In addition, no phase was observed in diffractograms due to W doping in ZnO matrix. An important effect of W incorporation in ZnO matrix was observed on the grain size and morphology as can be seen in FESEM images. Films optical parameters such as band gap, absorption index and refractive index of films are obtained from absorbance, transmittance and reflectance spectra in UV–Vis-NIR region. The PL spectra of films reveals quenching effect after adding W doping level. The TRPL spectra of films shows that the carrier decay time have been improved with increase in W doping concentrations. On the other hand, films UV detection performance are examined, which reveals significant improvement in response-recovery time, responsivity, external quantum efficiency and detectivity.