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Title: Localization landscape theory of disorder in semiconductors. II. Urbach tails of disordered quantum well layers

Journal Article · · Physical Review. B
 [1];  [2];  [2];  [3];  [3];  [3];  [4];  [4];  [4];  [1]
  1. Ecole Polytechnique, Univ. of Paris-Saclay, Palaiseau (France). Lab. of Condensed Matter Physics; Univ. of California, Santa Barbara, CA (United States). Dept. of Materials
  2. National Taiwan Univ., Taipei (Taiwan). Graduate Inst. of Photonics and Optoelectronics and Dept. of Electrical Engineering
  3. Univ. of California, Santa Barbara, CA (United States). Dept. of Materials
  4. Ecole Polytechnique, Univ. of Paris-Saclay, Palaiseau (France). Lab. of Condensed Matter Physics

Urbach tails in semiconductors are often associated to effects of compositional disorder. The Urbach tail observed in InGaN alloy quantum wells of solar cells and LEDs by biased photocurrent spectroscopy is shown to be characteristic of the ternary alloy disorder. The broadening of the absorption edge observed for quantum wells emitting from violet to green (indium content ranging from 0% to 28%) corresponds to a typical Urbach energy of 20 meV. A three-dimensional absorption model is developed based on a recent theory of disorder-induced localization which provides the effective potential seen by the localized carriers without having to resort to the solution of the Schrodinger equation in a disordered potential. This model incorporating compositional disorder accounts well for the experimental broadening of the Urbach tail of the absorption edge. For energies below the Urbach tail of the InGaN quantum wells, type-II well-to-barrier transitions are observed and modeled. This contribution to the below-band-gap absorption is particularly efficient in near-ultraviolet emitting quantum wells. When reverse biasing the device, the well-to-barrier below-band-gap absorption exhibits a red-shift, while the Urbach tail corresponding to the absorption within the quantum wells is blue-shifted, due to the partial compensation of the internal piezoelectric fields by the external bias. The good agreement between the measured Urbach tail and its modeling by the localization theory demonstrates the applicability of the latter to compositional disorder effects in nitride semiconductors.

Research Organization:
Univ. of California, Santa Barbara, CA (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office; French National Research Agency (ANR); Ministry of Science and Technology (MOST), Taipei (Taiwan)
Contributing Organization:
Ecole Polytechnique Paris National Taiwan University
Grant/Contract Number:
EE0007096; ANR-14-CE05-0048-01; MOST-104-2923-E-002-004-MY3; MOST-105-2221-E-002-098-MY3
OSTI ID:
1429092
Alternate ID(s):
OSTI ID: 1352104; OSTI ID: 1635239
Journal Information:
Physical Review. B, Vol. 95, Issue 14; ISSN 2469-9950
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 66 works
Citation information provided by
Web of Science

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Cited By (20)

Optical absorption edge broadening in thick InGaN layers: Random alloy atomic disorder and growth mode induced fluctuations journal January 2018
Alloy disorder limited mobility of InGaN two-dimensional electron gas journal June 2018
Three dimensional simulation on the transport and quantum efficiency of UVC-LEDs with random alloy fluctuations journal October 2018
Photocurrent measurements of InGaN/GaN quantum wells under hydrostatic and uniaxial pressure journal March 2019
Compensation between radiative and Auger recombinations in III-nitrides: The scaling law of separated-wavefunction recombinations journal November 2019
Application of localization landscape theory and the k · p model for direct modeling of carrier transport in a type II superlattice InAs/InAsSb photoconductor system journal January 2020
Resonant photoluminescence studies of carrier localisation in c-plane InGaN/GaN quantum well structures journal April 2018
Kinetic Monte Carlo simulations of the dynamics of a coupled system of free and localized carriers in AlGaN journal January 2020
Impact of alloy disorder on Auger recombination in single InGaN/GaN core-shell microrods journal December 2019
Many-body localization landscape journal January 2020
Electronic structure of semiconductor nanostructures: A modified localization landscape theory journal January 2020
Switching of exciton character in double InGaN/GaN quantum wells journal October 2018
Review—The Physics of Recombinations in III-Nitride Emitters journal January 2020
Resonant photoluminescence studies of carrier localisation in c-plane InGaN/GaN quantum well structures. text January 2018
Localization landscape theory of disorder in semiconductors I: Theory and modeling text January 2017
Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes text January 2017
Many-Body Localization Landscape text January 2019
Localization landscape for Dirac fermions journal February 2020
Anderson localisation in two dimensions: insights from Localisation Landscape Theory, exact diagonalisation, and time-dependent simulations preprint January 2020
Fast localization of eigenfunctions via smoothed potentials preprint January 2020

Figures / Tables (14)