Nanowire-Seeded Growth of Single-Crystalline (010) β-Ga2 O3 Nanosheets with High Field-Effect Electron Mobility and On/Off Current Ratio.

2D β-Ga2 O3 nanosheets, as fundamental materials, have great potential in next generations of ultraviolet transparent electrodes, high-temperature gas sensors, solar-blind photodetectors, and power devices, while their synthesis and growth with high crystalline quality and well-controlled orientation have not been reported yet. The present study demonstrates how to grow single-crystalline ultrathin quasi-hexagonal β-Ga2 O3 nanosheets with nanowire seeds and proposes a hierarchy-oriented growth mechanism. The hierarchy-oriented growth is initiated by epitaxial growth of a single-crystalline ( 2 - 01 ) β-Ga2 O3 nanowire on a GaN nanocrystal and followed by homoepitaxial growth of quasi-hexagonal (010) β-Ga2 O3 nanosheets. The undoped 2D (010) β-Ga2 O3 nanosheet field effect transistor has a field-effect electron mobility of 38 cm2 V-1 s-1 and an on/off current ratio of 107 with an average subthreshold swing of 150 mV dec-1 . The from-nanowires-to-nanosheets technique paves a novel way to fabricate nanosheets, which has great impact on the field of nanomaterial synthesis and growth and the area of nanoelectronics as well.