Direct observation of atomic columns in semiconductors by HREM at 400 kV

The different viewing axes of cubic diamond and zincblende type structures observable by HREM at 400 kV are investigated. Complete dynamical calculations are presented for the four orientations 〈100〉, 〈111〉, 〈110〉, and 〈013〉 in Si, Ge, and several III–V and II–VI compounds. It is shown both, experimentally and theoretically that true atomic imaging is possible in the 〈100〉, 〈111〉, and 〈013〉 orientations. Moreover atomic species can be identified in favourable compounds with rather different Z-values for the two 〈100〉 and 〈013〉 orientations.