IMPROVED MODELING OF EXCITONS IN TYPE-II SEMICONDUCTOR HETEROSTRUCTURES BY USE OF A 3-DIMENSIONAL VARIATIONAL FUNCTION

Citation
A. Bellabchara et al., IMPROVED MODELING OF EXCITONS IN TYPE-II SEMICONDUCTOR HETEROSTRUCTURES BY USE OF A 3-DIMENSIONAL VARIATIONAL FUNCTION, Physical review. B, Condensed matter, 50(16), 1994, pp. 11840-11844
Citations number
24
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
50
Issue
16
Year of publication
1994
Pages
11840 - 11844
Database
ISI
SICI code
0163-1829(1994)50:16<11840:IMOEIT>2.0.ZU;2-N
Abstract
Binding energies and oscillator strengths of excitons in staggered-lin eup heterostructures such as type-II quantum wells are calculated by a variational method, using a single parameter. This method involves th e effective attractive potential imposed by the confined carrier to it s unconfined companion. Contrary to previous comparable works, a three -dimensional trial function of the variable r (r=\r(e)-r(h)\) is used, instead of a two-dimensional function of the in-plane projection rho. Due to the large spatial extension along z of the wave function of th e unconfined carrier, the latter approximation commonly used up to dat e, is too drastic, even though it works reasonably well for type-I sys tems. This is demonstrated by comparison of both hypotheses for GaAs-A lAs systems: when using the 3D function, binding energies are increase d by up to 52%, while electron-hole overlap integrals can be enhanced by one order of magnitude.