Single cuprous oxide films synthesized by radical oxidation at low temperature for PV application

Cuprous oxide (Cu2O) films synthesis by radical oxidation with nitrogen (N-2) plasma treatment and different RF power at low temperature (500 degrees C) are studied in this paper. X-ray diffraction measurements show that synthesized Cu2O thin films grow on c-sapphire substrate with preferred (111) orientation. With nitrogen (N-2) plasma treatment, the optical bandgap energy is increased from 1.69 to 2.42 eV, when N-2 plasma treatment time is increased from 0 min to 40 min. Although the hole density is increased from 10(14) to 10(15) cm(-3) and the resistivity is decreased from 1879 to 780 Omega cm after N-2 plasma treatment, the performance of Cu2O films is poorer compared to that of Cu2O using RF power of 0. The fabricated ZnO/Cu2O solar cells based on Cu2O films with RF power of 0 W show a good rectifying behavior with a efficiency of 0.02%, an open-circuit voltage of 0.1 V, and a fill factor of 24%. (C) 2013 Optical Society of America