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Title: Growth optimization and optical properties of AlGaNAs alloys

The effect of Al on the surface morphology of chemical beam epitaxy grown AlGaNAs alloys is studied. Pits attributed to N clustering appearing on the dilute nitride surface become smaller, denser, and more uniformly distributed in the presence of Al. This reveals that the introduction of Al results in more homogenous N atoms spatial distribution. A growth temperature study reveals the formation of 3D structures at high temperature due to phase separation. The density of these structures decreases, while their diameter and height increase when the temperature is raised from 380 °C to 565 °C. At growth temperatures in the 380–420 °C range, the phase separation is suppressed and the growth mode is 2D. At 420 °C, the N incorporation is also maximized, making it the optimum temperature. The absorption coefficient and the bandgap of AlGaNAs alloys are extracted from transmittance measurement. A good agreement is obtained between the experimentally measured bandgap and the theoretical values calculated using the band anticrossing model. A bandgap as low as 1.22 eV was reached using Al and N concentrations of ∼15% and ∼3.4%, respectively.
Authors:
; ; ;  [1] ;  [2] ; ; ;  [3]
  1. Institut interdisciplinaire d'innovation technologique (3IT), Université de Sherbrooke, 3000, boul. Université, J1K 0A5 Sherbrooke, Québec (Canada)
  2. (LN2)- CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke J1K OA5, Québec (Canada)
  3. Cyrium Technologies Inc., 50 Hines Road, K2K 2M5 Ottawa, Ontario (Canada)
Publication Date:
OSTI Identifier:
22273504
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; ALUMINIUM ARSENIDES; CONCENTRATION RATIO; ELECTRONIC STRUCTURE; ENERGY GAP; EPITAXY; GALLIUM NITRIDES; MORPHOLOGY; OPTICAL PROPERTIES; OPTIMIZATION; SPATIAL DISTRIBUTION; SURFACES; TEMPERATURE DEPENDENCE