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Title: Suppression of the quantum-confined Stark effect in Al{sub x}Ga{sub 1−x}N/Al{sub y}Ga{sub 1−y}N corrugated quantum wells

We report comparative studies of 6-nm-thick Al{sub x}Ga{sub 1−x}N/Al{sub y}Ga{sub 1−y}N pyroelectric quantum wells (QWs) grown by plasma-assisted molecular beam epitaxy on c-sapphire substrates with a thick AlN buffer deposited under different growth conditions. The Al-rich growth conditions result in a 2D growth mode and formation of a planar QW, whereas the N-rich conditions lead to a 3D growth mode and formation of a QW corrugated on the size scale of 200–300 nm. Time-resolved photoluminescence (PL) measurements reveal a strong quantum-confined Stark effect in the planar QW, manifested by a long PL lifetime and a red shift of the PL line. In the corrugated QW, the emission line emerges 200 meV higher in energy, the low-temperature PL lifetime is 40 times shorter, and the PL intensity is stronger (∼4 times at 4.5 K and ∼60 times at 300 K). The improved emission properties are explained by suppression of the quantum-confined Stark effect due to the reduction of the built-in electric field within the QW planes, which are not normal to the [0001] direction, enhanced carrier localization, and improved efficiency of light extraction.
Authors:
; ; ; ; ; ; ;  [1] ; ; ;  [2]
  1. Ioffe Physical-Technical Institute, Russian Academy of Sciences, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation)
  2. Department of Physics, Chemistry and Biology, Linköping University, S-581 83 Linköping (Sweden)
Publication Date:
OSTI Identifier:
22217983
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 12; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ALUMINIUM NITRIDES; ELECTRIC FIELDS; MOLECULAR BEAM EPITAXY; PHOTOLUMINESCENCE; PLASMA; QUANTUM WELLS; RED SHIFT; SAPPHIRE; STARK EFFECT; TIME RESOLUTION; YTTRIUM NITRIDES