Regensburg 2000 – scientific programme

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HL: Halbleiterphysik

HL 42: Elektronentheorie

HL 42.9: Talk

Friday, March 31, 2000, 12:30–12:45, H14

Effect of interface roughness on optical intraband transitions — •M. Hackenberg, C. Metzner, and G.H. Döhler — Technische Physik I, Universität Erlangen, Erwin-Rommel-Strasse 1

Interface roughness is one of the major factors determining the line width of the intersubband transition in quantum wells. We analyze the effect of fluctuating hetero surfaces on the electron gas by direct computation of the resulting quantum states, using realistic microscopic models for the interface profiles. On the basis of these states, we calculate the intra-conduction band absorption spectrum for light polarized perpendicular and lateral to the layers, as a function of carrier density, well width and the structural interface parameters.

When the well width is gradually decreased, the electron gas undergoes at low densities a metal-insulator transition, finally approaching the limit of a random quantum dot array. This transition is accompanied by characteristic changes of the intra-subband absorption spectra, yielding important information about the interface morphology.