A new wide-bandgap perovskite semiconductor BaSnO3: high mobility, stability, and bipolar dopability

A wide-bandgap perovskite oxide semiconductor BaSnO3 was recently found to possess high mobility and excellent stability. Its single crystal mobility value of about 300 cm2/V·sec in the doping range of 1020/cm3, when n-type La dopants in place of Ba are used, is one of the highest among all the semiconductors. Furthermore, the oxygen diffusion constant in BaSnO3 was measured to be several orders of magnitude lower than the cuprates, manganites, and titanates. Taking advantage of such properties, excellent field effect transistors were recently demonstrated using amorphous gate oxides as well as a LaInO3 epitaxial gate oxide, which led to development of an all-perovskite transparent high mobility field effect transistor. In addition, p-type doping by K in place of Ba is feasible and the pn-junctions made with K-doped BaSnO3 and La-doped BaSnO3 were demonstrated to exhibit near-ideal IV characteristics. Moreover, 2DEG-like behavior is found at the polar interface of BaSnO3 and LaInO3. We will go over the parameters that control the 2DEG-like behavior and discuss the mechanism behind such behavior. In spite of these tremendous progresses, the device performances are currently limited by defects such as threading dislocations. For example, our recent photoconductivity study of BaSnO3 will shed some light on such defect states. Once all the major defects are removed, the perovskite oxide semiconductor BaSnO3 system is expected to offer much more opportunities for science and technology. In spite of these tremendous progresses, the device performances are currently limited by defects such as threading dislocations. For example, our recent photoconductivity study of BaSnO3 will shed some light on such defect states. Once all the major defects are removed, the perovskite oxide semiconductor BaSnO3 system is expected to offer much more opportunities for science and technology.