Shape analysis of single and stacked InAs quantum dots at the atomic level by cross-sectional STM

We present a study of InAs self-assembled quantum dots in GaAs by cross-sectional scanning tunneling microscopy (X-STM). Our results shows that the dots consist of an JnGaAs alloy and that the indium content increases towards the top. The analysis of the height versus base length relation obtained from cross-sectional images of the dots show that the shape of the dots resembles that of a truncated pyramid with a square base that is oriented along the [100] and [010] directions. Our results about the shape and size agree with the analysis of previous photocurrent measurements on these samples