Cross-sectional scanning tunneling microscopy of MBE-grown Si p-n junctions and Si/SiGe superlattices

We have used cross-sectional scanning tunneling microscopy and spectroscopy to study a Si (001) p-n junction and a Si/Si0.76Ge0.24 (001) superlattice grown by molecular-beam epitaxy. The shape of the band-edge profile in the p-n junction can be seen with a spatial resolution of better than 100 åA, and features in the electronic structure of the Si/Si0.76Ge0.24 superlattice have been detected with a spatial resolution of only a few nanometers. Topographic contrast between the Si and Si0.76Ge0.24 layers in the superlattice has also been observed. © 1993.