Low-temperature scanning tunneling microscope-induced luminescence of an InGaN/GaN multiquantum well

We report the scanning tunneling microscope-induced luminescence of an InGaN/GaN multiquantum well. Spectral analysis confirms the dominance of quantum well luminescence. This dominance is discussed in terms of the extent of band bending near the surface. The onset of light emission occurs at a bias larger than the emitted photon energy. This observation agrees with a tunneling in the GaN cap prior to a transport to the quantum well. Luminescence images exhibit features 30-100 nm in size and are discussed in relation to previous studies.