Photoconductivity study of spray pyrolized pure and Cu-modified SrTiO3 thin films

The SrTiO3 (STO) and Cu-STO nanostructured thin films were prepared using the spray pyrolysis technique. So prepared films were characterized for structural, electrical and optical and photoconductivity properties. The FE-SEM showed with inhomogeneous grain growth. Scherrer formula used to calculate particle size. The band gap, activation energies are estimated. AFM results were analyzed to estimate roughness. Absorbance and band gaps are calculated. The tungsten 100 W bulb was used to irradiate the films. The nature of I-V characteristics of the films changes with the ranges of applied bias. The effect of electric field and intensity relies photoconductivity of the films. The photo generated current Ip and dark current Id varies according to the power law I alpha V-m with the applied field and intensity of illumination, due to the defect related mechanism including both recombination centres and traps. The variation in linearity is attributed to flow of trap limited as well as space charge limited current inside the material. Doping of Cu led to the introduction of a high concentration of oxygen vacancies on the surface of the STO lattice. Consequently, to maintain the regional charge balance of STO, Cu(2+)could be substituted for Sr2+. Moreover, oxygen vacancies induced localized states into the band gap of the modified STO and acted as photoinduced charge traps, thus promoting the photoconductivity process. The photoconductivity of Cu modified films was found to be more than that of pure STO thin films. This study will have significant impact on the use of Cu-STO in optoelectronics devices. (c) 2020 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the International Conference on Advancement in Nanoelectronics and Communication Technologies.