Microstructure, morphology and sunlight response of cuprous oxide thin films

Cuprous oxide thin films were successfully synthesized on FTO substrates via the electrochemical method by changing the deposition potential. The effects of deposition potential on the microstructure, morphology, optical band gap and photoresponse of the thin films were investigated. The results revealed that intensity of (111) diffraction peak and preferential orientation along (111) plane increase with increasing the absolute value of deposition potential. The thin film with the more negative deposition potential has an increased average particle size and compact degree. The optical band gap of the sample deposited at −0.5 eV presents the largest value of 1.82 eV. Upon sunlight illumination, the photocurrent of thin film rises quickly at first and then gets slower. The slow photoresponse may be attributed to the capture of carriers by deep level traps in our case.