Photoluminescence of CdSe quantum dots grown on tilted ZnSe/GaAs[100]

Recently, CdSe quantum dots (QDs) have been studied extensively with the aim for the application in opto-electronic devices. It is well known the self-assembled CdSe dots on ZnSe[100] grow by Stranski-Krastanow (SK) mode. One of the problems in CdSe dot preparation is how to control the dot size. In the previous study, monitoring the specular beam intensity during the growth, we confirmed the SK dots originate immediately after the third CdSe monolayer is formed on 2ML-CdSe. In other words, only the third CdSe monolayer converts to dots and 2ML-CdSe (WL: wetting layer) remains on ZnSe, and dot size becomes large by ripening during the third layer deposition. Since primary dots originate by the condensation of CdSe monolayer, it is expected that dot generation depend on the shape of the surface terrace. Here CdSe dots were fabricated by an alternate molecular beam supply on ZnSe buffer layer grown on GaAs[100]. Photoluminescence (PL) was measured at the liquid He temperature by an excitation of the He-Cd laser.