Phase separation growth of InGaAs cap layer on InAs/GaAs quantum dots

Abstract

The mechanisms responsible for the shift of the photoluminescence spectrum to longer wavelength by depositing an InCaAs cap layer on InAs/GaAs quantum dots are studied in detail. It is demonstrated that the phase separation growth of InAs and GaAs rather than the stress in the lnAs quantum dots is the main reason for the wavelength shifts. Also, AFM image of single lnAs quantum dot is observed. The reason for the differences between AFM and SEM images is discussed.

Effects of the thickness of GaAs spacer layers on the structure of multilayer stacked InAs quantum dots

“…The resolution of AFM is limited by the sharpness and shape of the tip whose normal radius of curvature is 20-60 nm [10]. In particular, lateral resolution is much more dependent on the dimension of the tip than vertical resolution in nanometer-sized samples because of the measuring geometry between the tip and sample [11]. Considering the QD structure by TEM, it is believed that the lateral dimension of QDs measured by AFM is not reliable although their vertical dimension by AFM is reasonable.…”