Regensburg 2000 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 27: Poster II: SiC (1-7), Ultrakurzzeitdynamik (8-15), Halbleiterlaser (16-20), GaN (21-38), III-V Halbleiter (39-56), Photovoltaik (57-64), Störstellen (65-68), Tern
äre Halbleiter (69-70)

HL 27.26: Poster

Mittwoch, 29. März 2000, 14:00–19:00, A

Indium Surface Segregation and Polarization Charge Screening in (In,Ga)N/GaN Single- and Multi-Quantum-Wells — •Oliver Mayrock, Hans-Jürgen Wünsche, and Fritz Henneberger — Humboldt-Universität zu Berlin, Institut für Physik, Photonik, Invalidenstr.110, D-10115 Berlin, Germany

We calculate transition energies, electron-hole overlap integrals and emission lineshapes of (In,Ga)N/GaN single- and multi-quantum-wells in a two-band effective-mass model and investigate the influence of indium surface segregation, background doping density, thickness of the cap layer, number of quantum wells, and polarity. Indium surface segregation results in a blueshift of the emission energy and in a decreased electron-hole overlap. Background doping influences the band edge alignment not only via screening of the polarization charge at the material interfaces by free carriers, but also via ionized dopants in depletion layers. Therefore, the position of the QW in the sample with respect to an extended depletion layer—which is shown to exist in Ga-face grown material with n-type doping—severely affects transition energy and electron-hole overlap.