The stoichiometry of InAs quantum dots determined by cross-sectional scanning tunneling microscopy

We present cross-sectional scanning tunneling microscopy results of InAs qu antum dots. The observed material contrast is both of electronic and struct ural origin, the latter resulting from strain relaxation upon cleavage. By comparing the experimental data with simulations of strain relaxation, the dots were found to consist of pure InAs with a Ga content of up to 1%.