Size and density estimation of self‐assembled InAs quantum dots on GaAs(001) substrate through the analysis of RHEED patterns

Abstract

Size and density of self-assembled InAs quantum dots grown on GaAs(001) surface were calculated through the analysis of characteristic RHEED intensity and patterns, on the assumption that the logical thickness of two dimensional wetting layer should have a discrete value. The estimated results were compared with those of AFM direct observation. Pyramidal and round island dot models were introduced for the estimation, which are consisted of continuous flat InAs layers. During dot growth, substrate was not rotated to develop dot density gradient. Estimated results were not exactly matched with AFM observed results, because the estimated results were based on in-situ RHEED intensity measurement, while AFM is ex-situ observation method. Nevertheless, estimation results showed an interesting tendency that less developed small dot had the shape closer to pyramidal model, while over developed big dot had the shape closer to round island model.