Improvement of the hole mobility of SnO epitaxial films grown by pulsed laser deposition

Stannous oxide, SnO, is a promising material for practical applications as a p-type transparent oxide semiconductor. However, in its thin-film form, the reported semiconducting properties of SnO are unfortunately insufficient for the development of oxide devices. In this work, we report that the hole mobility of SnO epitaxial films grown by pulsed laser deposition can be improved by reducing the growth temperature. The hole mobility is estimated to be approximately 10 cm² V^-1 s^-1 at room temperature, which is nearly four times higher than the one originally reported for epitaxial films fabricated at the conventional growth temperature. In addition, the observed carrier density of the fabricated SnO films is slightly lower compared with that of the ones fabricated at the conventional growth temperature. This suggests that the Sn vacancy formation as a hole carrier dopant is suppressed by the reduction in the growth temperature. This result offers the key for the improvement of the performance of oxide thin-film devices.