Improvement of physical and electrochemical properties of Cu2O thin films with Fe ions doping towards optoelectronic applications

Abstract

Pure and doped Cu2O thin films were deposited on FTO substrate with various Fe dopant concentrations employing low-cost electrodeposition technique. All thin films were successfully characterized employing XRD, SEM, PL spectroscopy, UV–vis spectrophotometer, and photocurrent measurement. XRD results indicate the formation of cubic structure of thin films where all grown grains were well oriented along (111) diffraction plane at different dopant concentrations. The crystal size of doped Cu2O thin films was calculated from the Scherrer equation were the values range from 24.95 to 31.75 nm. The creation of grains similar pyramid-shaped for grown thin films is proven by SEM results. PL results reveal the characteristic emission peaks of Cu2O thin films at 521 and 704 nm which are attributed to the inter-band transitions and Cu vacancies or O interstitial, respectively. Moreover, PL intensity changed with doping process due to the integration of Fe3+ ions in interstitial positions or/and Cu sites. The optical measurements indicate that thin films have optical absorption edge which located between 490 and 550 nm that attributed to Cu2O band gap. The estimated Eg for pure and doped Cu2O thin films was founded to be in the range from 2.1 to 2.59 eV. The photocurrent measurements signal that electrodeposited Cu2O films are p-type semiconductors. Furthermore, the doping process enhancement the photocurrent where more visible light could be more captured and therefore improvement of electron-hole production. The results show that Fe doped Cu2O thin films are talented candidate for the optoelectronic applications such as sensors and solar cells.