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Lookup NU author(s): Dr Matthew Kitchin,
Professor Milan Jaros
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We report a systematic study into carrier scattering by isovalent defects within GaSb/InAs superlattices. The heterostructure system which we investigate has attracted recent interest as the active region of a photodetector for very long wavelength infrared (VLWIR) (≥ 12 μm) radiation. To achieve our objective, we employed models of the electronic band structure and scattering cross-section. We considered isolated, substitutional defects at each atom site throughout the unit cell in turn and found that the scattering magnitude generally follows the carrier envelope function, being greatest where the overlap of charge with the defect is highest. We scrutinized the contribution of lattice relaxation around defects to the overall scattering, by comparing calculations where this effect was, in turn, included and excluded. We identified some anomalous contributions of relaxation to both qualitative and quantitative features of the cross-section. Physical mechanisms to explain these effects must be arrived at in order to attain satisfactory characterization of these materials, highlighting the need for both microscopic models and further research. Additional modelling of islands of such defects indicated that the cross-section is proportional to the square of the number of constituent atoms, for both carrier types (holes and electrons) and each defect type. This article demonstrates important links between key growth issues and the dynamical properties of these novel semiconductor devices. © 2003 Elsevier Science B.V. All rights reserved.
Author(s): Kitchin MR, Jaros M
Publication type: Article
Publication status: Published
Journal: Physica E: Low-dimensional Systems and Nanostructures
ISSN (print): 1386-9477
ISSN (electronic): 1873-1759
Publisher: Elsevier BV
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