We present direct experimental evidence of Anderson localization induced by the intrinsic alloy compositional disorder of InGaN/GaN quantum wells. Our approach relies on the measurement of the luminescence spectrum under local injection of electrons from a scanning tunneling microscope tip into a near-surface single quantum well. Fluctuations in the emission line shape are observed on a few-nanometer scale. Narrow emission peaks characteristic of single localized states are resolved. Calculations in the framework of the localization landscape theory provide the effective confining potential map stemming from composition fluctuations. This theory explains well the observed nanometer scale carrier localization and the energies of these Anderson-type localized states. The energy spreading of the emission from localized states is consistent with the usually observed very broad photo- or electroluminescence spectra of InGaN/GaN quantum well structures.
|Original language||English (US)|
|Journal||Physical Review B|
|State||Published - Jul 19 2018|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-09
Acknowledgements: We thank Aurélien David for fruitful discussions. This work was supported by the French National Research Agency (ANR) and Taiwanese Ministry of Science and Technology (MOST) (CRIPRONI project: Grants No. ANR-14-CE05-0048-01, No. MOST-104-2923-E-002-004-MY3, and No. MOST-105-2221-E-002-098-MY3), and by ARPA-E, U.S. Department of Energy (program DE-EE0007096), the UCSB Solid State Lighting and Energy Electronics Center, and KACST-KAUST-UCSB Solid State Lighting Program (SSLP).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.