Comparison of Si doping effect on GaN nanowires and films synthesized by metal-organic chemical vapor deposition

We investigated Si doping effect on GaN nanowires and GaN films grown by metal-organic chemical vapor deposition (MOCVD). Si as n-type dopant is incorporated to GaN nanowires and GaN films controlled by SiH ₄ flow rate (0, 1, 5, 8, and 10 sccm). The charge concentration and mobility of GaN films increased and decreased, respectively, as increasing the SiH ₄flow rate, whereas those for GaN nanowires were not influenced by the SiH ₄ flow rate. Significant vacancies and impurities resulted in the intense yellow band in GaN nanowires as compared with GaN films, which leads to the large device-to-device variation and negligible dependence of Si doping and the SiH ₄ flux rate on the electrical properties of GaN nanowires.