Transport properties of the two-dimensional electron gas in Al/sub x/Ga/sub 1-x/N/GaN heterostructures

Magnetotransport properties of modulation-doped Al/sub x/Ga/sub 1-x/N/GaN heterostructures were studied at low temperatures and high magnetic fields. The strong Shubnikov-de Hass oscillations with the double periodicity is clearly observed, indicating the two-dimensional electron gas (2DEG) occupation of the double subbands in the triangular quantum well at the heterointerfaces. It is determined that the 2DEG occupation of the double subbands occurs when the 2DEG sheet concentration reaches 9.0 /spl times/ 10/sup 12/cm/sup -2/, and the energy separation between the first and the second subbands is 75 meV. The quantum scattering time related to the first subband is determined to be 8.4 /spl times/ 10/sup -14/ s. The mobilities of the 2DEG in the first and the second subbands, magnetointersubband scattering oscillations of the 2DEG and the spin splitting of the 2DEG have also been studied.