Towards high-mobility In2xGa2–2xO3 nanowire field-effect transistors
Recently, owing to the excellent electrical and optical properties, n-type In2O3 nanowires (NWs) have attracted tremendous attention for application in memory devices, solar cells, and ultra-violet photodetectors. However, the relatively low electron mobility of In2O3 NWs grown by chemical vapor deposition (CVD) has limited their further utilization. In this study, utilizing in-situ Ga alloying, highly crystalline, uniform, and thin In2xGa2−2xO3 NWs with diameters down to 30 nm were successfully prepared via ambient-pressure CVD. Introducing an optimal amount of Ga (10 at.%) into the In2O3 lattice was found to effectively enhance the crystal quality and reduce the number of oxygen vacancies in the NWs. A further increase in the Ga concentration adversely induced the formation of a resistive β-Ga2O3 phase, thereby deteriorating the electrical properties of the NWs. Importantly, when configured into global back-gated NW field-effect transistors, the optimized In1.8Ga0.2O3 NWs exhibit significantly enhanced electron mobility reaching up to 750 cm2·V–1·s–1 as compared with that of the pure In2O3 NW, which can be attributed to the reduction in the number of oxygen vacancies and ionized impurity scattering centers. Highly ordered NW parallel arrayed devices were also fabricated to demonstrate the versatility and potency of these NWs for next-generation, large-scale, and high-performance nanoelectronics, sensors, etc.
KeywordsIn2O3 In2xGa2−2xO3 nanowire chemical vapor deposition mobility oxygen vacancy
Unable to display preview. Download preview PDF.
We acknowledge the General Research Fund (No. CityU 11275916) and the Theme-based Research Scheme (No. T42-103/16-N) of the Research Grants Council of Hong Kong SAR, China, the National Natural Science Foundation of China (Nos. 51672229 and 61605024), the Science Technology and Innovation Committee of Shenzhen Municipality (No. JCYJ20160229165240684) and a grant from the Shenzhen Research Institute, City University of Hong Kong.
- Kim, J.; Rim, Y. S.; Chen, H. J.; Cao, H. H.; Nakatsuka, N.; Hinton, H. L.; Zhao, C. Z.; Andrews, A. M.; Yang, Y.; Weiss, P. S. Fabrication of high-performance ultrathin In2O3 film field-effect transistors and biosensors using chemical lift-off lithography. ACS Nano 2015, 9, 4572–4582.CrossRefGoogle Scholar
- Yang, Z.-X.; Wang, F. Y.; Han, N.; Lin, H.; Cheung, H.-Y.; Fang, M.; Yip, S.; Hung, T.; Wong, C.-Y.; Ho, J. C. Crystalline GaSb nanowires synthesized on amorphous substrates: From the formation mechanism to p-channel transistor applications. ACS Appl. Mater. Interfaces 2013, 5, 10946–10952.CrossRefGoogle Scholar