Photoluminescence properties of intra-well exciton migration in Zn1−Cd Se quantum wells

Determination of the minimum island size for full exciton localization due to thickness fluctuations in Zn1−Cd Se quantum wells

“…Calculations were made for two structurally different Znl-xCdxSe QWs [2,6,7]. The parameters used in calculation are listed in Table 1.…”

“…Many of the phenomena related to exciton localization and phonon assisted migration can be observed when studying the photoluminescence (PL) vs. temperature characteristics of high quality QWs. The analysis requires a clear identification of the different excitonic emission mechanisms which may be present in the QW PL spectrum [2]. Bound excitons (BX) [3] and biexcitons (BB) [4,5] have been assigned to optical transitions in the PL spectra of ZnI _ 1 Cd, Se QWs.…”

“…Bound excitons (BX) [3] and biexcitons (BB) [4,5] have been assigned to optical transitions in the PL spectra of ZnI _ 1 Cd, Se QWs. In previous papers we have analyzed in detail the mechanisms of exciton localization and exciton migration as a function of temperature for the case of two structurally different Zn -,Cd, Se QWs grown by molecular beam epitaxy (MBE) with different barrier materials [2,6,7]. Based on those studies we have made estimates of the relative total area of islands with different thickness, but that analysis does not give information about the area of individual islands [2].…”

“…In previous papers we have analyzed in detail the mechanisms of exciton localization and exciton migration as a function of temperature for the case of two structurally different Zn -,Cd, Se QWs grown by molecular beam epitaxy (MBE) with different barrier materials [2,6,7]. Based on those studies we have made estimates of the relative total area of islands with different thickness, but that analysis does not give information about the area of individual islands [2]. In the following we will present a calculation of the minimum size (Li, Ly) of an (N + 1) island that is necessary to produce full localization of excitons, that is, when AE • U = Els(N) -Eis(N + 1).…”