Capacitance measurements as a new tool to investigate the electronic states of dislocations in semiconductors

The effect of edge dislocations on the capacitance of surface barrier diodes made of n-germanium is investigated as a function of temperature. It is shown that the edge dislocations decrease the diode capacitance and that, at large reverse bias, from this decrease the occupation ratio f(T) of the dislocation levels can be obtained. Similar results are also obtained from Hall effect measurements made on the same samples previously measured by the capacitance method, thus indicating that the latter method is a valid alternative to the former in the study of the electrical properties of dislocations in semiconductors. The results are also in quantitative agreement with those already found by other authors and lend support to the model of a partially filled dislocation band in germanium, with a neutral level 0.09 eV above the top of the valence band.