Highly Oriented Polycrystalline Cu2O Film Formation Using RF Magnetron Sputtering Deposition for Solar Cells

Room temperature sputtering deposition and re-crystallization of the deposited thin films by rapid thermal annealing have been evaluating in detail as a formation method of Cu2O active layer for solar cells, which minimize thermal budget in fabrication processes. Single phase polycrystalline Cu2O films were obtained by a magnetron rf sputtering deposition and its crystallinity and electrical characteristics were controlled by the annealing. Hall mobility was improved up to 17 cm(2)V(-1)s(-1) by the annealing at 600 degrees C for 30s. Since this value was smaller than 47 cm(2)V(-1)s(-1) of the film deposited under thermal equilibrium state using pulsed laser deposition at 600 degrees C, some contrivances were necessary to compensate the deficiency. It was understood that the sputter-deposited Cu2O films on (111)-oriented Pt films were strongly oriented to (111) face also by the self-assembly and the crystallinity was improved by the annealing preserving its orientation. The sputter-deposited film quality was expected to become equivalent to the pulsed laser deposition film from the results of X-ray diffractometry and photoluminescence.