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Title: High pressure and time resolved studies of optical properties of n-type doped GaN/AlN multi-quantum wells: Experimental and theoretical analysis

Abstract

High-pressure and time-resolved studies of the optical emission from n-type doped GaN/AlN multi-quantum-wells (MQWs) with various well thicknesses are analysed in comparison with ab initio calculations of the electronic (band structure, density of states) and optical (emission energies and their pressure derivatives, oscillator strength) properties. The optical properties of GaN/AlN MQWs are strongly affected by quantum confinement and polarization-induced electric fields. Thus, the photoluminescence (PL) peak energy decreases by over 1 eV with quantum well (QW) thicknesses increasing from 1 to 6 nm. Furthermore, the respective PL decay times increased from about 1 ns up to 10 μs, due to the strong built-in electric field. It was also shown that the band gap pressure coefficients are significantly reduced in MQWs as compared to bulk AlN and GaN crystals. Such coefficients are strongly dependent on the geometric factors such as the thickness of the wells and barriers. The transition energies, their oscillator strength, and pressure dependence are modeled for tetragonally strained structures of the same geometry using a full tensorial representation of the strain in the MQWs under external pressure. These MQWs were simulated directly using density functional theory calculations, taking into account two different systems: the semi-insulating QWs and the n-doped QWs with themore » same charge density as in the experimental samples. Such an approach allowed an assessment of the impact of n-type doping on optical properties of GaN/AlN MQWs. We find a good agreement between these two approaches and between theory and experimental results. We can therefore confirm that the nonlinear effects induced by the tetragonal strain related to the lattice mismatch between the substrates and the polar MQWs are responsible for the drastic decrease of the pressure coefficients observed experimentally.« less

Authors:
 [1];  [2]; ;  [1]; ; ; ;  [3];  [4]; ;  [5];  [6];  [1];  [2]
  1. Institute of Physics Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02-668 Warsaw (Poland)
  2. (Poland)
  3. Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw (Poland)
  4. University of Warsaw, Faculty of Physics, Pasteura 5, 02-093 Warsaw (Poland)
  5. Université Grenoble-Alpes, 38000 Grenoble (France)
  6. (France)
Publication Date:
OSTI Identifier:
22598822
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 9; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM NITRIDES; COMPARATIVE EVALUATIONS; CRYSTAL DEFECTS; CRYSTALS; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; DOPED MATERIALS; ELECTRIC FIELDS; GALLIUM NITRIDES; NONLINEAR PROBLEMS; N-TYPE CONDUCTORS; OPTICAL PROPERTIES; OSCILLATORS; PHOTOLUMINESCENCE; PRESSURE COEFFICIENT; PRESSURE DEPENDENCE; QUANTUM WELLS; THICKNESS; TIME RESOLUTION

Citation Formats

Kaminska, A., Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Dewajtis 5, 01-815 Warsaw, Jankowski, D., Sobczak, K., Strak, P., Sakowski, K., Grzanka, E., Krukowski, S., Korona, K. P., Beeler, M., Monroy, E., CEA Grenoble, INAC-PHELIQS, 17 av. des Martyrs, 38000 Grenoble, Borysiuk, J., and University of Warsaw, Faculty of Physics, Pasteura 5, 02-093 Warsaw. High pressure and time resolved studies of optical properties of n-type doped GaN/AlN multi-quantum wells: Experimental and theoretical analysis. United States: N. p., 2016. Web. doi:10.1063/1.4962282.
Kaminska, A., Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Dewajtis 5, 01-815 Warsaw, Jankowski, D., Sobczak, K., Strak, P., Sakowski, K., Grzanka, E., Krukowski, S., Korona, K. P., Beeler, M., Monroy, E., CEA Grenoble, INAC-PHELIQS, 17 av. des Martyrs, 38000 Grenoble, Borysiuk, J., & University of Warsaw, Faculty of Physics, Pasteura 5, 02-093 Warsaw. High pressure and time resolved studies of optical properties of n-type doped GaN/AlN multi-quantum wells: Experimental and theoretical analysis. United States. doi:10.1063/1.4962282.
Kaminska, A., Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Dewajtis 5, 01-815 Warsaw, Jankowski, D., Sobczak, K., Strak, P., Sakowski, K., Grzanka, E., Krukowski, S., Korona, K. P., Beeler, M., Monroy, E., CEA Grenoble, INAC-PHELIQS, 17 av. des Martyrs, 38000 Grenoble, Borysiuk, J., and University of Warsaw, Faculty of Physics, Pasteura 5, 02-093 Warsaw. 2016. "High pressure and time resolved studies of optical properties of n-type doped GaN/AlN multi-quantum wells: Experimental and theoretical analysis". United States. doi:10.1063/1.4962282.
@article{osti_22598822,
title = {High pressure and time resolved studies of optical properties of n-type doped GaN/AlN multi-quantum wells: Experimental and theoretical analysis},
author = {Kaminska, A. and Cardinal Stefan Wyszynski University, College of Science, Department of Mathematics and Natural Sciences, Dewajtis 5, 01-815 Warsaw and Jankowski, D. and Sobczak, K. and Strak, P. and Sakowski, K. and Grzanka, E. and Krukowski, S. and Korona, K. P. and Beeler, M. and Monroy, E. and CEA Grenoble, INAC-PHELIQS, 17 av. des Martyrs, 38000 Grenoble and Borysiuk, J. and University of Warsaw, Faculty of Physics, Pasteura 5, 02-093 Warsaw},
abstractNote = {High-pressure and time-resolved studies of the optical emission from n-type doped GaN/AlN multi-quantum-wells (MQWs) with various well thicknesses are analysed in comparison with ab initio calculations of the electronic (band structure, density of states) and optical (emission energies and their pressure derivatives, oscillator strength) properties. The optical properties of GaN/AlN MQWs are strongly affected by quantum confinement and polarization-induced electric fields. Thus, the photoluminescence (PL) peak energy decreases by over 1 eV with quantum well (QW) thicknesses increasing from 1 to 6 nm. Furthermore, the respective PL decay times increased from about 1 ns up to 10 μs, due to the strong built-in electric field. It was also shown that the band gap pressure coefficients are significantly reduced in MQWs as compared to bulk AlN and GaN crystals. Such coefficients are strongly dependent on the geometric factors such as the thickness of the wells and barriers. The transition energies, their oscillator strength, and pressure dependence are modeled for tetragonally strained structures of the same geometry using a full tensorial representation of the strain in the MQWs under external pressure. These MQWs were simulated directly using density functional theory calculations, taking into account two different systems: the semi-insulating QWs and the n-doped QWs with the same charge density as in the experimental samples. Such an approach allowed an assessment of the impact of n-type doping on optical properties of GaN/AlN MQWs. We find a good agreement between these two approaches and between theory and experimental results. We can therefore confirm that the nonlinear effects induced by the tetragonal strain related to the lattice mismatch between the substrates and the polar MQWs are responsible for the drastic decrease of the pressure coefficients observed experimentally.},
doi = {10.1063/1.4962282},
journal = {Journal of Applied Physics},
number = 9,
volume = 120,
place = {United States},
year = 2016,
month = 9
}
  • In order to describe theoretically the tuning of the optical gain by hydrostatic pressure in GaInNAs/GaAs quantum wells (QWs), the optical gain calculations within kp approach were developed and applied for N-containing and N-free QWs. The electronic band structure and the optical gain for GaInNAs/GaAs QW were calculated within the 10-band kp model which takes into account the interaction of electron levels in the QW with the nitrogen resonant level in GaInNAs. It has been shown that this interaction increases with the hydrostatic pressure and as a result the optical gain for GaInNAs/GaAs QW decreases by about 40% and 80%more » for transverse electric and transverse magnetic modes, respectively, for the hydrostatic pressure change from 0 to 40 kilobars. Such an effect is not observed for N-free QWs where the dispersion of electron and hole energies remains unchanged with the hydrostatic pressure. This is due to the fact that the conduction and valence band potentials in GaInAs/GaAs QW scale linearly with the hydrostatic pressure.« less
  • The results of comprehensive theoretical and experimental study of binary GaN/AlN multi-quantum well (MQW) systems oriented along polar c-direction of their wurtzite structure are presented. A series of structures with quantum wells and barriers of various thicknesses were grown by plasma-assisted molecular-beam epitaxy and characterized by x-ray diffraction and transmission electron microscopy. It was shown that in general the structures of good quality were obtained, with the defect density decreasing with increasing quantum well thickness. The optical transition energies in these structures were investigated comparing experimental measurements with ab initio calculations of the entire GaN/AlN MQW structure depending on themore » QW widths and strains, allowing for direct determination of the energies of optical transitions and the electric fields in wells/barriers by electric potential double averaging procedure. Photoluminescence (PL) measurements revealed that the emission efficiency as well as the shape of luminescence spectra correlated well with their structural quality. Additionally, due to the Quantum-Confined Stark Effect, the emission energy decreased by over 1 eV for quantum well thicknesses increasing from 1 nm up to 6 nm, and this effect was accompanied by the drastic drop of the PL efficiency. The experimental results are consistent with theoretical models. Comparison of experimental data obtained by a number of different characterization techniques with the density functional theory results received on the same geometry structure allowed to prove directly the theoretical models and to determine the polarization and the oscillator strengths in the AlN/GaN nitride systems for the first time.« less
  • The pressure effect on the magnetic field induced type I{endash}type II transition is studied in a CdTe/Cd{sub 1{minus}x}Mn{sub x}Te (x=0.24) single quantum well. Photoluminescence measurements under hydrostatic pressures up to 1.07 GPa and long pulsed magnetic fields up to 60 T with a pulse duration of 2 s are reported. The pressures were generated in a plastic diamond anvil cell. A bend toward lower energies (additional red shift) is observed above 28.5 T in magnetic field dependence of the exciton energy for a 13 {Angstrom} thick quantum well. We attribute this red shift to a phenomenon preceding the type I{endash}typemore » II transition after a comparison with a simple quantum mechanical calculation. The onset field of the additional red shift increases by 3.4 T by applying a pressure of 1.07 GPa. Spin{endash}spin coupling between the exciton and the Mn ion in the interface region is also investigated and found to be enhanced by pressure. {copyright} {ital 1999 American Institute of Physics.}« less
  • The optical and electrical characteristics of pulsed discharges in pure Ar at pressures of up to 7 atm, at which the discharge becomes unstable, are studied in a simple experimental device with automatic preionization. The gas temperature in the discharge is estimated from the width of the recorded emission spectrum. An analytical model of the vibrational relaxation of Ar*{sub 2}(v) is used to better determine the constants of the vibrational-translational relaxation of Ar*{sub 2}(v) molecules in their collisions with Ar atoms. The zero-dimensional numerical model of a pulsed discharge in Ar is modified. The experimental and calculated results are comparedmore » in detail. Good agreement is achieved between the measured and calculated time dependences of the electrode voltage and the intensity of spontaneous emission in the pressure range of 1-6 atm, as well as between the measured and calculated values of the gas temperature at pressures of 3-6 atm. Preliminary results from numerical studies of the possibility of achieving generation are discussed.« less
  • Spin splitting of conduction-band energy levels in a modulation-doped InP/In{sub 0.77}Ga{sub 0.23}As/InP quantum well has been studied by Shubnikov{endash}de Haas oscillations. By analyzing the characteristic beating pattern of the oscillations the coupling constant {alpha} for spin-orbit interaction was determined. Biasing a gate on top of a Hall bar was used to modify the strength of the spin-orbit coupling. The measured spin-orbit coupling parameter {alpha} is quantitatively explained by utilizing a refined envelope-function-approximation theory for heterostructures. {copyright} {ital 1997} {ital The American Physical Society}