Magnetotransport properties of the two-dimensional electron gas in AlxGa1-xN/GaN heterostructures under illumination

Magnetotransport properties of the two-dimensional electron gas (2DEG) in the triangular quantum well at Al_xGa_1-xN/GaN heterointerfaces have been investigated by means of temperature dependent Shubnikov-de Haas (SdH) measurements at low temperatures and high magnetic fields under illumination. After the illumination of the heterostructures, the 2DEG concentration increases and the SdH oscillation amplitudes are enhanced when there is no additional subband occupation. As the second subband becomes to be populated, the electron mobility decreases for the intersubband scattering and the 2DEG concentration of the first subband deceases. We suggest that the illumination decreases the electric field and weakens the quantum confinement of the triangular quantum well at Al_xGa_1-xN/GaN heterointerfaces.