Characterization of the two-dimensional electron gas in Al/sub x/Ga/sub 1-x/N/GaN heterostructures with two subbands occupied

Magnetotransport properties of the two-dimensional electron gas (2DEG) in Al/sub x/Ga/sub 1-x/N/GaN heterostructures have been investigated. We extrapolate that the second subband in the triangular quantum well at the heterointerface starts to be populated at a 2DEG concentration of about 7.23 /spl times/ 10/sup 12/ cm/sup -1/. The quantum scattering time related to the first subband is obtained as 0.144-0.146 ps for the heterostructures. Intersubband scattering is also observed in the heterostructures.