High-Mobility In and Ga co-doped ZnO Nanowires for High-Performance Transistors and Ultraviolet Photodetectors

Due to the unique properties, ZnO nanostructures have received considerable attention for electronics and optoelectronics; however, intrinsic ZnO nanomaterials are usually suffered from large concentrations of lattice defects, such as oxygen vacancy, restricting their material performance. Here, for the first time, highly-crystalline In and Ga co-doped ZnO nanowires (NWs) are achieved by the ambient-pressure chemical vapor deposition. As contrasted to the conventional elemental doping, this In and Ga co-doping can not only enhance the carrier concentration, but also suppress the formation of oxygen vacancy within the host lattice. Importantly, this co-doping is also believed to effectively minimize the generation of lattice stain defects because of the optimal ionic sizes of both In and Ga dopants. When configured into field-effect transistors (FET), these co-doped NWs exhibit an enhanced average electron mobility of 315 cm2 V-1 s-1 and an impressive on/off current ratio of 1.87x108, which are already higher than other ZnO NW devices previously reported. In addition, these NW device can as well perform efficient ultraviolet photodetection with an improved responsivity of 1.41x107 A W-1, an excellent EQE up to 6.72x109 and a fast response time down to 0.32 s at under 261 nm irradiation. Highly-ordered NW parallel array thin-film transistors and photodetectors are also constructed to demonstrate their promising potential for high-performance device applications.