Thin, free-standing Cu2O substrates via thermal oxidation for photovoltaic devices

Cu 2 O is a promising, earth-abundant alternative to traditional photovoltaic materials (CIGS, CdTe, etc.) because of its low cost, high availability, and straightforward processing. We report a method to fabricate Cu 2 O substrates with thicknesses of less than 20 microns which may be handled and processed into devices. Development of thinner Cu 2 O substrates is essential as extrinsic doping has been impossible thus far, and intrinsic Cu 2 O is highly resistive. Hall measurements indicate that the substrates had Hall mobilities of 10-20 cm 2 V -1 s -1 and carrier concentrations on the order of 10 14 cm -3 . Current-voltage characteristics of these Cu 2 O substrates were derived from liquid junction Schottky barrier device measurements which indicate open circuit voltages of Voc ~ 600 mV.