Renormalization of the band gap in highly photoexcited type-II ZnSe/BeTe structures

Journal Article · Sun Feb 15 04:00:00 EST 2009 · Semiconductors

DOI:https://doi.org/10.1134/S1063782609020183· OSTI ID:21260422

Yakovlev, D R ^[1]; Waag, A ^[2]

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1. University of Dortmund, Experimentelle Physik II (Germany)
2. Braunschweig Technical University, Institute of Semiconductor Technology (Germany)

For the type-II ZnSe/BeTe heterostructures, a large ({approx}0.1 eV) red shift of the edge of interband recombination in the ZnSe layers is observed at high densities of spatially separated photoexcited electrons and holes ({approx}10{sup 13} cm{sup -2}). The observed magnitude of renormalization of the band gap exceeds the magnitudes predicted by the multiparticle theory for dense type-I electron-hole systems at the same concentrations of two-dimensional charge carriers. Numerical calculations show that macroscopic electric fields induced by separated charges have a profound effect on the energy of direct transitions in type-II structures, resulting in an additional decrease in the energy of the transitions. In wide structures, where the ZnSe layer thickness is {>=} 15 nm, the renormalization effect is less pronounced. This is attributed to incomplete spatial separation of photoexcited charge carriers in the case of profound band bending and, thus, to the less-pronounced effect of electric fields.

• OSTI ID: 21260422
• Journal Information: Semiconductors, Journal Name: Semiconductors Journal Issue: 2 Vol. 43; ISSN SMICES; ISSN 1063-7826
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BERYLLIUM TELLURIDES
CHARGE CARRIERS
ELECTRIC FIELDS
ELECTRONS
HOLES
LAYERS
MILLI EV RANGE
RECOMBINATION
RENORMALIZATION
ZINC SELENIDES