Strain effects and band offsets in GaAs/InGaAs strained layered quantum structures

• Published in: Journal of applied physics 1989-08, Vol.66 (4), p.1739-1747
• Main Authors: ARENT, D. J, DENEFFE, K, VAN HOOF, C, DE BOECK, J, BORGHS, G
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.344395

Strained single quantum wells composed of GaAs/InGaAs/GaAs were grown by molecular beam epitaxy and characterized at room temperature by photoreflectance and at 6 and 77 K by photoluminescence spectroscopy. For the InGaAs/GaAs heterojunction, utilizing a band offset ratio of 85:15 (conduction band:valence band) for the intrinsic (nonstrained) interface and a contribution of the hydrostatic compression to the valence band movement corresponding to the pressure sensitivity of the spin orbit band, excellent agreement is found between calculated excitonic transition energies and those found by experiment at all temperatures studied. Our analysis indicates that material parameters and the combined strain components used to calculate band structure are not temperature dependent to our degree of sensitivity. An empirical equation, which differs slightly from that for bulk InGaAs crystals, describing the nonstrained band-gap energy as a function of In fraction at 77 K is presented. The difference between band offset ratios for the intrinsic and strained heterojunction are found to be significant and the relative merits of each are discussed.