Cyclotron resonance studies of two-dimensional electrons confined at the GaN/AlGaN
interface are presented. The value of the 2D-electron cyclotron mass is determined and
discussed in view of nonparabolicity and polaron effects. The influence of nonparabolicity is
enhanced by the spatial confinement of electrons and is calculated in the triangular well
approximation. After subtraction of nonparabolicity corrections, the same polaron mass
(0.223±0.011) m0 is obtained for 2D and bulk electrons in GaN.