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HL: Fachverband Halbleiterphysik

HL 43: Theory of electronic structure

HL 43.6: Vortrag

Donnerstag, 29. März 2007, 15:15–15:30, H14

Self-consistent k.p envelope function method for InAs/GaSb broken gap superlattices — •Till Andlauer, Tobias Zibold, and Peter Vogl — Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, D-85748 Garching

A novel charge self-consistent k.p envelope function method is presented for the calculation of the electronic structure of type-II semiconductor heterostructures with broken gap. Such heterostructures are relevant for the development of infrared lasers as well as infrared detectors. Standard multi-band k.p approaches fail to yield the correct occupation of electronic states in broken gap heterostructures, because strong hybridization of conduction band and valence band states makes it impossible to occupy electron and hole states separately. In our method, we occupy all included subbands with electrons according to Fermi statistics and subsequently subtract a positive background charge that guarantees charge neutrality. We present results, such as gaps, subband dispersions, masses, and local charge densities, for strained intrinsic InAs/GaSb (001)-superlattices as a function of layer thickness and bias. We find good agreement for the effective bandgap with experimental data [1,2]. [1] L. L. Chang et al., J. Vac. Sci. Technol. 19, 589 (1981). [2] H. Mosheni et al., Appl. Phys. Lett. 71, 1403 (1997).