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Title: Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs

Abstract

We investigate the optical transitions of GaN{sub x}As{sub 1−x} quantum wells (QWs) embedded in wider band gap AlGaAs. A combination of absorption and emission spectroscopic techniques is employed to systematically investigate the properties of GaNAs QWs with N concentrations ranging from 0 – 3%. From measurement of the photocurrent spectra, we find that besides QW ground state and first excited transition, distinct increases in photocurrent generation are observed. Their origin can be explained by N-induced modifications in the density of states at higher energies above the QW ground state. Photoluminescence experiments reveal that peak position dependence with temperature changes with N concentration. The characteristic S-shaped dependence for low N concentrations of 0.5% changes with increasing N concentration where the low temperature red-shift of the S-shape gradually disappears. This change indicates a gradual transition from impurity picture, where localized N induced energy states are present, to alloying picture, where an impurity-band is formed. In the highest-N sample, photoluminescence emission shows remarkable temperature stability. This phenomenon is explained by the interplay of N-induced energy states and QW confined states.

Authors:
 [1];  [2]; ;  [3]
  1. International Center for Young Scientists, National Institute for Materials Science, 305-0047 Tsukuba (Japan)
  2. Photovoltaic Materials Unit, National Institute for Materials Science, 305-0047 Tsukuba (Japan)
  3. Photonic Materials Unit, National Institute for Materials Science, 305-0047 Tsukuba (Japan)
Publication Date:
OSTI Identifier:
22611548
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTROSCOPY; ALUMINIUM ARSENIDES; CONCENTRATION RATIO; DENSITY OF STATES; ELECTRONIC STRUCTURE; GALLIUM ARSENIDES; GALLIUM NITRIDES; GROUND STATES; IMPURITIES; MODIFICATIONS; NITROGEN ADDITIONS; PHOTOCURRENTS; PHOTOLUMINESCENCE; QUANTUM WELLS; RED SHIFT; SPACE DEPENDENCE; SPECTRA; STABILITY; TERNARY ALLOY SYSTEMS; X-RAY SPECTROSCOPY

Citation Formats

Elborg, M., E-mail: ELBORG.Martin@nims.go.jp, Noda, T., Mano, T., and Sakuma, Y. Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs. United States: N. p., 2016. Web. doi:10.1063/1.4953894.
Elborg, M., E-mail: ELBORG.Martin@nims.go.jp, Noda, T., Mano, T., & Sakuma, Y. Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs. United States. doi:10.1063/1.4953894.
Elborg, M., E-mail: ELBORG.Martin@nims.go.jp, Noda, T., Mano, T., and Sakuma, Y. 2016. "Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs". United States. doi:10.1063/1.4953894.
@article{osti_22611548,
title = {Optical transitions in GaNAs quantum wells with variable nitrogen content embedded in AlGaAs},
author = {Elborg, M., E-mail: ELBORG.Martin@nims.go.jp and Noda, T. and Mano, T. and Sakuma, Y.},
abstractNote = {We investigate the optical transitions of GaN{sub x}As{sub 1−x} quantum wells (QWs) embedded in wider band gap AlGaAs. A combination of absorption and emission spectroscopic techniques is employed to systematically investigate the properties of GaNAs QWs with N concentrations ranging from 0 – 3%. From measurement of the photocurrent spectra, we find that besides QW ground state and first excited transition, distinct increases in photocurrent generation are observed. Their origin can be explained by N-induced modifications in the density of states at higher energies above the QW ground state. Photoluminescence experiments reveal that peak position dependence with temperature changes with N concentration. The characteristic S-shaped dependence for low N concentrations of 0.5% changes with increasing N concentration where the low temperature red-shift of the S-shape gradually disappears. This change indicates a gradual transition from impurity picture, where localized N induced energy states are present, to alloying picture, where an impurity-band is formed. In the highest-N sample, photoluminescence emission shows remarkable temperature stability. This phenomenon is explained by the interplay of N-induced energy states and QW confined states.},
doi = {10.1063/1.4953894},
journal = {AIP Advances},
number = 6,
volume = 6,
place = {United States},
year = 2016,
month = 6
}
  • GaNAs/Al{sub 0.35}Ga{sub 0.65}As multiple quantum wells (MQWs) with nitrogen δ-doping were fabricated on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. High controllability of nitrogen-concentrations in the MQWs was achieved by tuning nitrogen δ-doping time. The maximum nitrogen concentration in the MQWs was 2.8%. The MQWs exhibit intense, narrow photoluminescence emission.
  • The authors investigated the synthesis of GaIn(N)As/Ga(N)As multiple quantum wells by molecular beam epitaxy. Introducing N into the GaInAs appears to suppress the incorporation of In as indicated by reflective high-energy electron diffraction (RHEED). This effect is mainly due to the N-induced enhancement of In surface segregation at the growth front and is evidenced by the increasing damping rate of RHEED oscillations with N incorporation. The N-induced enhancement of In segregation in the GaInNAs quantum wells is confirmed by secondary-ion-mass spectroscopy and high-resolution x-ray diffractions, and its origin is discussed.
  • A series of AlGaAs/InGaAs/AlGaAs quantum-well heterostructures with different quantum-well depths and approximately the same concentrations of two-dimensional electrons is grown by molecular-beam epitaxy. The built-in electric field in the grown samples is determined from the photoreflectance data and, on this basis, the energy-band structure in the quantum-well region is calculated. It is found that the highest mobility {mu}{sub e} of two-dimensional electrons is attained in the sample with a barrier-layer thickness of L{sub b} = 11 nm. Measurements of the photoluminescence spectra and the band-structure calculations demonstrate that, as the quantum well becomes closer to the surface, the doping profilemore » broadens due to diffusion and segregation processes. The nonmonotonic dependence of {mu}{sub e} on the distance between the surface and the quantum well is explained.« less
  • The optical modulation technique of photoreflectance (PR) has been applied to characterize the interband transitions in GaAs/AlGaAs multiple quantum wells (MQW) and modulation-doped heterojunctions at room temperature. The spectra of the MQW show derivative-like reflectance features due to allowed interband transitions from heavy and light hole subbands to conduction subbands, and the E0(Gamma/8,v/ to Gamma/6,c/) transitions of the AlGaAs layers. The data are consistent with a square well calculation using a conduction-band offset of 60 percent of the band-gap discontinuity. For modulation-doped heterojunctions, a correlation is observed between a PR feature approximately 18 meV above the GaAs fundamental gap andmore » the presence of a two-dimensional electron gas. 14 references.« less
  • We have investigated a growth technique to realize high-quality multiple stacking of self-assembled InAs quantum dots (QDs) on GaAs (001) substrates, in which GaN{sub x}As{sub 1-x} dilute nitride material was used as a strain compensation layer (SCL). The growth was achieved by atomic hydrogen-assisted rf molecular beam epitaxy, and the effect of strain compensation was systematically investigated by using high-resolution x-ray diffraction measurements. By controlling the net average lattice strain to a minimum by covering each QD layer with a 40-nm-thick GaN{sub 0.005}As{sub 0.995} SCL, we obtained a superior QD structure with no degradation in size homogeneity. Further, no dislocationsmore » were generated even after 30 layers of stacking, and the area density of QDs amounted to as high as 3x10{sup 12} cm{sup -2}. The photoluminescence peak linewidth was improved by about 22% for QDs embedded in GaNAs SCLs as the accumulation of lattice strain with increasing growth of QD layers was avoided, which would otherwise commonly lead to degradation of size homogeneity and generation of dislocations.« less