Abstract: The transport behaviors of two GaN/AlGaN two-dimensional electron systems (2DESs) grown on Si substrates were studied, and a SiN x treatment employed in sample fabrication enhanced the conductance of one of the 2DESs. We study the electron heating effect in the 2DESs experimentally, with resistances as self-thermometers. The relation of T e∼I 1.42 was obtained, which is in contrast to T e∼I 0.5 in the resistivity peaks in a GaAs/AlGaAs 2DES. This may be caused by the scattering effect in this sample. [Copyright &y& Elsevier]