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We study the effects of intense THz laser field on the ground-state binding energy of heavy hole excitons confined in GaAs spherical quantum dots. The calculation is performed using the variational method in the framework of the single band effective mass theory. Our results show that (i) the laser electric field lowers the binding energy for all quantum dot radii, making the exciton clustered near the centre of the dot, (ii) the binding energy is mainly due to the dressed potential making the kinetic part insensitive to the field and (iii) the behaviour of the exciton, under the approximations used, can be modelled by a unique set of plots, depending on the material only via its excitonic units. [ABSTRACT FROM AUTHOR]

Using the variational method in real space and the effective-mass theory, we present quite an advanced semi-analytic approach susceptible for calculating the binding energy EB of Wannier excitons in semiconductor quantum dot structures with rectangular and parabolic shapes of the confining potential in the so-called strong-confinement regime. Illustration is given for CdS, ZnSe, CdSe, GaAs structures of crystallites for both rectangular and parabolic quantum dots, and it displays a very good agreement between the experimental and theoretical results reported in literature. [ABSTRACT FROM AUTHOR]

Excitons in inhomogenous quantum nanospheres have been theoretically studied within the effective mass approximation. An infinite deep potential has been used to describe the effects of quantum confinement. The binding energy with or without an applied electric field is determined by the Ritz variational method taking into account the correlation between the electron and the hole in the trial wave function. It appears that the binding energy strongly depends on the core and shell radii. The existence of a radius ratio critical value has been shown: it may be used to distinguish between tridimensional and spherical surface confinement. The influence of a uniform electric field is analyzed. It has been found that the Stark effect appears even for very small sizes and that the energy shift is more significant when the exciton is near the spherical surface. [Copyright &y& Elsevier]