Enhancement of hole mobility in high-rate reactively sputtered Cu2O thin films induced by laser thermal annealing

Abstract

In presented work, a reactive high-power impulse magnetron sputtering (r-HiPIMS) was used for high-rate deposition ( 170 nm/min) of Cu2O films. Films were deposited on a standard soda-lime glass (SLG) substrate at a temperature of 190C. As-deposited films exhibit poor hole mobility in the orders of 1 cm2/Vs. We have systematically studied the effect of laser thermal annealing (LTA) procedure performed using high-power infrared laser under different laser parameters (number of pulses, length of the pulse). We have found, LTA procedure could significantly enhance the hole mobility (up to 24 cm2/Vs in our case). We have also fitted the results of a temperature-dependent Hall measurement to clarify the mechanism of the reported increase in hole mobility. Moreover, we have discussed the effect of the LTA procedure on microstructure (crystallinity, surface morphology) and on the value of optical band gap.