Rigorous excitonic theory of field dependent superlattice absorption

Abstract

We have performed calculations of the field dependent excitonic absorption spectra of semiconductor superlattices in a model which is capable of fully taking into account the Coulomb interaction and both bound and continuum excitonic states. Results are obtained for the complete range of fields from the Franz-Keldysh to the Wannier-Stark regime. The lineshapes of the excitonic spectra are shown to resemble the derivative of the corresponding single particle spectra with respect to the wavelength. In addition characteristic excitonic features have been found, which also have been observed in photocurrent spectra

Microscopic theory of the intracollisional field effect in semiconductor superlattices

“…Different approaches have been applied, each of which presents certain advantages in studying distinct aspects of the problem. Linder et al, 1,2 starting from the single-particle eigenstates of the problem @i.e., Wannier-Stark~WS! states along the growth and field direction, multiplied by two-dimensional plane waves~PW's!#, proposed a direct diagonalization of the superlattice Hamiltonian including Coulomb interaction within the Hartree-Fock approximation.…”

Theory of quasiequilibrium nonlinear optical absorption in semiconductor superlattices

“…The high energy shoulder is related to the miniband dispersion. 5 With increasing carrier density the strength of the excitonic absorption decreases due to phase-space filling and screening of the attractive e-h interaction. Above the Mott-density ͑here about 5ϫ10 16 cm Ϫ3 ), the exciton completely disappears from the spectrum.…”

“…excitonic Wannier-Stark ladders. 5,6 Although there are a number of experimental investigations of nonlinear optical absorption spectra of superlattices, [7][8][9] up to now no systematic calculation of optical spectra of excited or inverted systems has been published.…”

Confinamento de estados eletrônicos e vibracionais em microestruturas semicondutoras com progressiva redução da dimensionalidade

“…[Schmidt 1994]. Com isso se fez possível o estudo detalhado da região de transição entre os regimes FK e SW. Utilizando uma teoria que inclui efeitos excitônicos [Linder 1993], os autores concluíram que as oscilações FK e as escadas SW coexistem no regime intermediário, o que leva à complexidade das formas de linha observadas (e à dificuldade de interpretação de nossos dados com respeito a essa região de campo efetivo).…”