Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 10: Nitrides: Devices
HL 10.6: Vortrag
Montag, 12. März 2018, 16:30–16:45, EW 203
Evidence of nanoscale Anderson localization induced by intrinsic compositional disorder in InGaN/GaN quantum wells by scanning tunneling luminescence spectroscopy — •Wiebke Hahn1, Jean-Marie Lentali1, Petr Polovodov1, Nathan Young2, Shuji Nakamura2, James S. Speck2, Claude Weisbuch1,2, Marcel Filoche1, Fouad Maroun1, Lucio Martinelli1, Yves Lassailly1, and Jacques Peretti1 — 1Laboratoire de Physique de la Matière Condensée, Ecole polytechnique, CNRS, Université Paris Saclay, Palaiseau Cedex, France — 2Materials Department, University of California, Santa Barbara, USA
In nitride ternary alloys, intrinsic compositional disorder, resulting from the random distribution of atoms on the crystal lattice, induces strong electronic localization effects. We will present direct experimental evidences of Anderson localization induced at a scale of a few nanometers by the intrinsic alloy compositional disorder in an InGaN/GaN quantum well (QW). The experiment consists in locally injecting electrons from a scanning tunneling microscope (STM) tip into a p-type heterostructure incorporating an InGaN/GaN QW nearby the surface. The luminescence spectrum from the electrons captured in the QW is detected as a function of the injecting tip position. Spatial fluctuations of the luminescence peak energy and linewidth are observed on the scale of a few nanometers, characteristic of disorder-induced carrier localization. A model based on the so-called localization landscape theory accounts well for the observed nanometer scale carrier localization and the fluctuations in the luminescence peak energy.