Planar anisotropic Shubnikov-de-Haas oscillations of two-dimensional electron gas in AlN/GaN heterostructure

摘要

Two-dimensional electron gas (2DEG) buried in ultrathin barrier AlN/GaN heterostructures is the key to exploit high-speed and high-power devices in the aspect of modern semiconductor electronics. Here, we report Shubnikov-de-Haas oscillations of the 2DEG in an AlN/GaN heterostructure with planar anisotropy along [11-20] and [1-100] axes. The effective mass extracted from oscillations exhibits an evident disparity, as (0.19 +/- 0.02)m(e) along the [11-20] axis and (0.24 +/- 0.02)m(e) along the [1-100] axis. Meanwhile, the quantum scattering time is obviously different along the aforementioned directions, with 0.08 vs 0.26 ps for the first subband and 0.19 vs 0.27 ps for the second subband. Both the effective mass and the quantum scattering time contribute to the anisotropy of the quantum mobility, which are 750 and 1907 cm(2)/V s for E-1 and 1760 and 1980 cm(2)/V s for E-2 along [11-20] and [1-100] axes, respectively. These parameters are obviously crucial in designing devices using AlN/GaN heterostructures.