Magnetotransport measurement of effective mass, quantum scattering time, and alloy scattering potential of polarization-doped 3D electron slabs in graded-AlGaN

摘要

By applying the technique of polarization bulk-doping in graded AlGaN, it has been possible to create high-mobility three-dimensional electron slabs. Such 3D electron slabs are observed to exhibit clearly resolved Shubnikov de-Haas oscillations. From a temperature-dependent study of the oscillations, we measure the effective mass (m~* = 0.21m_0) and the quantum scattering time (τ_q = 0.3 ps) of carriers in the slabs. An analysis of the ratio of quantum and classical scattering times with the scattering mechanisms leads to the first direct measurement of the alloy scattering potential in the AlGaN system (V_0 = 1.8 eV).