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
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.