Exciton behavior in GaAs/AlGaAs coupled double quantum wells with interface disorder

Theoretical and experimental study of the excitonic binding energy in GaAs/AlGaAs single and coupled double quantum wells

“…Table 2 shows the comparison between the theoretical values obtained by the MLC method in conjunction with the approximation suggested by Zhao et al and the experimental results for dimensionality and effective mass obtained for all heterostructures. For CDQW5 with 35% Al it was considered the fit for the higher energy channel observed at the PL band, while for CDQW30 with the same Al concentration it was considered the fit for the lower energy channel (these two channels are related to the structural configuration which best represents the nominal dimensions of the mini-wells in each CDQW [18]). …”

“…The split of the PL bands is due to the existence of bimodal heterointerface roughness in the CDQWs. The details of the results obtained for this sample are discussed in two specific works previously published [18,19].…”

Poços Quânticos Duplos Acoplados.

“…Este aumento na FWHM do pico de PL está relacionado à intensificação dos efeitos relacionados às flutuações no potencial de confinamento com o aumento na espessura da barreira central (LOPES et al, 2010;POÇAS et al, 2006). Essas flutuações de potencial surgem devido às variações aleatórias na espessura dos mini-poços (rugosidades de interface) e/ou na composição química da liga (desordem composicional) que constitui as barreiras laterais e central, as quais perturbam os níveis de energia.…”

“…Em poços mais estreitos há uma maior contribuição dos efeitos das rugosidades de interface para as flutuações de potencial (LOPES et al, 2010;POÇAS et al, 2006), o que também contribui para que a FWHM aumente à medida que a barreira central se torna mais espessa.…”

Exciton-related energies of the 1s-like states of excitons in GaAs-Ga1−xAlxAs double quantum wells

“…Optical processes in low dimensional semiconductors are affected by several factors such as applied electric and magnetic fields, hydrostatic pressure, confining potential, interface disorder, intense laser field radiation [1][2][3][4][5][6][7]. Among these phenomena, those related with exciton and impurity states are the most difficult to treat theoretically due to the lack of analytical expressions for the wave functions corresponding to the bound states of electron-hole pairs or electron-impurity centers, respectively.…”