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Photoreflectance Spectroscopy Investigation of GaN–AlGaN Quantum Well Structures
Author(s) -
Ochalski T.J.,
Gil B.,
Bretag T.,
Lefebvre P.,
Grandjean N.,
Massies J.,
Leroux M.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199911)216:1<221::aid-pssb221>3.0.co;2-f
Subject(s) - quantum well , exciton , molecular beam epitaxy , spectroscopy , optoelectronics , excited state , materials science , oscillator strength , wide bandgap semiconductor , nitride , quantum , semiconductor , condensed matter physics , epitaxy , optics , physics , atomic physics , nanotechnology , spectral line , laser , quantum mechanics , layer (electronics)
Room‐temperature photoreflectance spectroscopy is performed on a series of GaN–AlGaN quantum wells grown by molecular beam epitaxy. We show that the potentialities of this powerful investigation method previously demonstrated on many low‐dimensional systems can be extended to nitride‐based quantum wells for accurate large‐scale characterisation. In particular, this technique allows us to get rid of optical interferences that usually prevent the observation of free‐exciton transitions below the band‐gap of GaN. Such transitions occur in wide quantum wells, due to large built‐in electric fields which also quench the oscillator strength of the transitions. Also, this technique allows us to magnify the features of confined excited states, which are difficult to observe by standard reflectance.