Intersubband absorption at 1.5-3.5 µm in GaN/AlN multiple quantum wells grown by molecular beam epitaxy on sapphire
2007 (English)In: Physica status solidi, ISSN 0370-1972, Vol. 244, no 8, 2892-2905 p.Article in journal (Refereed) Published
Ten and twenty period multiple quantum well structures with 1.5-5.4 nm GaN wells and 1.2-5.1 nm AlN barriers were grown on sapphire by molecular beam epitaxy. Layer thicknesses were determined by X-ray diffraction measurements and simulations. Reciprocal space mapping showed that the relaxation of the quantum well layers was independent of the buffer layer thickness. Intersubband absorption was observed by Fourier transform infrared spectroscopy at λ ∼ 1.5-3.5 μm. Monolayer fluctuations in the quantum well width induced multiple peaks in spectra, which were well fitted to Lorentzian peaks of only 57 meV linewidth. Samples were very homogeneous as the absorption peak energy varied less than 1% along ∼4 cm on 2 inch wafers. The intersubband transition energies were calculated considering the conduction-band nonparabolicity, built-in fields, strain, and many-body effects. The calculation and comparison to the fitted Lorentzian peak energies indicated a moderate blueshift due to many-body effects. It was shown by both experiments and calculations that the AlN barrier width affects the intersubband transition energy.
Place, publisher, year, edition, pages
2007. Vol. 244, no 8, 2892-2905 p.
many-body corrections, optical-transitions, wavelength-range, gan, superlattices, parameters, exchange, diodes, layer
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-6660DOI: 10.1002/pssb.200675606ISI: 000248712800019ScopusID: 2-s2.0-34547784042OAI: oai:DiVA.org:kth-6660DiVA: diva2:11432
QC 201009032006-12-152006-12-152016-05-09Bibliographically approved