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

Cuprous oxide (Cu(2)O) films synthesis by radical oxidation with nitrogen (N(2)) plasma treatment and different RF power at low temperature (500 °C) are studied in this paper. X-ray diffraction measurements show that synthesized Cu(2)O 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 Ω cm after N(2) plasma treatment, the performance of Cu(2)O films is poorer compared to that of Cu(2)O using RF power of 0. The fabricated ZnO/Cu(2)O solar cells based on Cu(2)O 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%.