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Title: Height stabilization of GaSb/GaAs quantum dots by Al-rich capping

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Solar and Thermal Energy Conversion (CSTEC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1370081
DOE Contract Number:
SC0000957
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 2; Journal Issue: 9; Related Information: CSTEC partners with University of Michigan (lead); Kent State University
Country of Publication:
United States
Language:
English

Citation Formats

Smakman, E. P., DeJarld, M., Luengo-Kovac, M., Martin, A. J., Sih, V., Koenraad, P. M., and Millunchick, J. Height stabilization of GaSb/GaAs quantum dots by Al-rich capping. United States: N. p., 2014. Web. doi:10.1063/1.4895783.
Smakman, E. P., DeJarld, M., Luengo-Kovac, M., Martin, A. J., Sih, V., Koenraad, P. M., & Millunchick, J. Height stabilization of GaSb/GaAs quantum dots by Al-rich capping. United States. doi:10.1063/1.4895783.
Smakman, E. P., DeJarld, M., Luengo-Kovac, M., Martin, A. J., Sih, V., Koenraad, P. M., and Millunchick, J. Mon . "Height stabilization of GaSb/GaAs quantum dots by Al-rich capping". United States. doi:10.1063/1.4895783.
@article{osti_1370081,
title = {Height stabilization of GaSb/GaAs quantum dots by Al-rich capping},
author = {Smakman, E. P. and DeJarld, M. and Luengo-Kovac, M. and Martin, A. J. and Sih, V. and Koenraad, P. M. and Millunchick, J.},
abstractNote = {},
doi = {10.1063/1.4895783},
journal = {APL Materials},
number = 9,
volume = 2,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}
  • GaSb quantum dots (QDs) in a GaAs matrix are investigated with cross-sectional scanning tunneling microscopy (X-STM) and photoluminescence (PL). We observe that Al-rich capping materials prevent destabilization of the nanostructures during the capping stage of the molecular beam epitaxy (MBE) growth process and thus preserves the QD height. However, the strain induced by the absence of destabilization causes many structural defects to appear around the preserved QDs. These defects originate from misfit dislocations near the GaSb/GaAs interface and extend into the capping layer as stacking faults. The lack of a red shift in the QD PL suggests that the preservedmore » dots do not contribute to the emission spectra. We suggest that a better control over the emission wavelength and an increase of the PL intensity is attainable by growing smaller QDs with an Al-rich overgrowth.« less
  • The optical and structural properties of In{sub 0.15}Ga{sub 0.85}As/In{sub x}Al{sub y}Ga{sub z}As/GaAs quantum wells with embedded InAs quantum dots (QDs) were investigated by the photoluminescence (PL), its temperature dependence, X-ray diffraction (XRD), and high resolution (HR-XRD) methods in dependence on the composition of capping In{sub x}Al{sub y}Ga{sub z}As layers. Three types of capping layers (Al{sub 0.3}Ga{sub 0.7}As, Al{sub 0.10}Ga{sub 0.75}In{sub 0.15}As, and Al{sub 0.40}Ga{sub 0.45}In{sub 0.15}As) have been used and their impact on PL parameters has been compared. Temperature dependences of PL peak positions in QDs have been analyzed in the range of 10–500 K and to compare with the temperaturemore » shrinkage of band gap in the bulk InAs crystal. This permits to investigate the QD material composition and the efficiency of Ga(Al)/In inter diffusion in dependence on the type of In{sub x}Al{sub y}Ga{sub z}As capping layers. XRD and HR-XRD used to control the composition of quantum well layers. It is shown that QD material composition is closer to InAs in the structure with the Al{sub 0.40}Ga{sub 0.45}In{sub 0.15}As capping layer and for this structure the emission 1.3 μm is detected at 300 K. The thermal decay of the integrated PL intensity has been studied as well. It is revealed the fast 10{sup 2}-fold thermal decay of the integrated PL intensity in the structure with the Al{sub 0.10}Ga{sub 0.75}In{sub 0.15}As capping layer in comparison with 10-fold decay in other structures. Finally, the reasons of PL spectrum transformation and the mechanism of PL thermal decay for different capping layers have been analyzed and discussed.« less
  • We investigated the effects of the GaAs capping temperature on the morphological and photoluminescence (PL) properties of InAs quantum dots (QDs) on GaAs(001). The broadband tuning of the emission wavelength from 1.1 to 1.3 μm was achieved at room temperature by only adjusting the GaAs capping temperature. As the capping temperature was decreased, the QD shrinkage due to In desorption and In-Ga intermixing during the capping process was suppressed. This led to QDs with a high aspect ratio, and resultantly, the emission wavelength shifted toward the longer-wavelength side. In addition, the linearly polarized PL intensity elucidated anisotropic characteristics reflecting the shapemore » anisotropy of the embedded QDs, in which a marked change in polarization anisotropy occurred at capping temperatures lower than 460 °C.« less
  • Strain engineering during the capping of III-V quantum dots has been explored as a means to control the height of strained self-assembled quantum dots. Results of Kinetic Monte Carlo simulations are confronted with cross-sectional Scanning Tunnel Microscopy (STM) measurements performed on InAs quantum dots grown by molecular beam epitaxy. We studied InAs quantum dots that are capped by In{sub x}Ga{sub (1−x)}As layers of different indium compositions. Both from our realistic 3D kinetic Monte Carlo simulations and the X-STM measurements on real samples, a trend in the height of the capped quantum dot is found as a function of the latticemore » mismatch between the quantum dot material and the capping layer. Results obtained on additional material combinations show a generic role of the elastic energy in the control of the quantum dot morphology by strain engineering during capping.« less
  • No abstract prepared.