Cross-Sectional Atomic Force Imaging of Semiconductor Heterostructures

We performed imaging of semiconductor heterostructures, in particular GaAs-AlGaAs quantum wells and quantum wires, by atomic force microscopy (AFM) of the cleaved edge of the samples. We used two methods to transform the alloy composition into height differences, measurable by AFM: natural oxidation and selective etching. The AFM allows visualization of nanostructures over large areas (up to 100 x 100 mu m(2)) with nm resolution. We obtain images with quality approaching that of transmission electron microscopy (TEM) images. Moreover, sample preparation is much simpler compared with other techniques such as TEM and thus can be used for routine measurements.