Photocarrier generation in CuxO thin films deposited by radio frequency sputtering

Abstract

Copper oxides (CuxO) thin films were deposited using radio frequency (RF) sputtering on glass substrates. By tuning the argon (Ar) partial pressure during deposition, cuprous oxide (Cu2O), cupric oxide (CuO), or their mixed phase could be achieved. Drastic variations in the Hall mobility, hole density, and resistivity of the samples were observed due to the presence of different phases in the films. Kelvin probe studies indicate that the photo-generated carriers have lower recombination rate in pure Cu2O phase. This was further validated by transient absorption measurements, where the estimated carrier lifetime for Cu2O was much larger that other phases.