Electrical transport of an AlGAN/GaN two dimensional electrong gas

摘要

An Al_xGa_(1-x)N two-dimensional electron gas structure with x chemical bounds 0.13 deposited by molecular beam epitaxy on a GaN layer grwon by organometallic vapor phase epitaxy on a sapphire substrate was characterized. Hall effect measurements gave a sheet electron concentration of 5.1 x10~(12) cm~(-2) and a mobility of 1.9x10~4 cm~2/Vs at 10 K. Mobility spectrum analysis showed single-carrier tranport and negligible parallel conduction at low temperatures. SThe sheet carrier concentrations determined from Shubnikov-de haas magnetoresistance oscillations were in good agreement with the Hall data. The electron effective mass was determined to be 0.21 +- 0.006 m_0 based on the temperature dependence of the amplitude of Shubnikov-de Haas oscillations. The quantum lifetime was about one-fifth of the transport lifetime of 2.3x10~(12) s.