Characterization of semiconductor heterostructures and quantum dots by friction force microscopy

The capability of friction force microscopy to obtain compositional maps of semiconductor structures grown by molecular beam epitaxy was studied. Experiments on InP/InGaAs multiquantum wells determined a compositional spatial resolution of 3 nm. Additionally, variations in indium concentration smaller than 10% were detected in InxGa1 − xAs structures. Friction maps of InAs and InSb quantum dots on InP(001) are also presented. The experimental results show that the frictional force is sensitive to the presence or absence of a wetting monolayer. Based on these experiments, the potential of friction force microscopy to develop a spatially resolved spectroscopy is discussed.