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THz intersubband transitions in AlGaN/GaN multi‐quantum‐wells
Author(s) -
Beeler Mark,
Bougerol Catherine,
BelletAmalaric Edith,
Monroy Eva
Publication year - 2014
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201300431
Subject(s) - quantum well , optoelectronics , materials science , absorption (acoustics) , infrared , molecular beam epitaxy , diffraction , doping , terahertz radiation , fourier transform infrared spectroscopy , infrared spectroscopy , layer (electronics) , optics , epitaxy , chemistry , physics , nanotechnology , laser , organic chemistry , composite material
Various designs of AlGaN/GaN structures displaying intersubband absorption in the THz spectral range are reported upon. Firstly, samples with 3‐layer quantum wells (step‐quantum‐wells) displaying far‐infrared intersubband absorption are presented. Theoretical analysis of the reproducibility issues associated to this architecture is done, and a more robust design based on 4‐layer quantum wells is proposed. Such a structure has been fabricated by plasma‐assisted molecular‐beam epitaxy using two Al effusion cells to produce three AlGaN concentrations, without growth interruptions. Samples have been structurally validated by transmission electron microscopy and X‐ray diffraction. Fourier transform infrared spectroscopy measurements show far‐infrared absorption of TM‐polarized light, which gets broader and deeper for increasing doping levels.