Dislocations and point defects introduce energy levels deep in the gap, which dramatically change the material electrical properties. Because of the coexistence of a multitude of dislocation types and dislocation-point defect interaction mechanisms, it would be highly desirable to identify the particular type of defect related to specific traps.
The electrical activity of extended defects (planar precipitates and dislocations) is here examined in terms of their recombination activity, investigated by electron as well as light beam induced current methods of scanning microscopy.
Besides, a scanning modification of spectroscopy is used to identify traps at individual defects. The method, named quenched infra-red beam induced current, combines the scanning light beam induced current technique with the spectroscopie bulk analysis called “infrared quenching of photoconductivity”.
Defect energy levels are found on the basis of the particular features of the beam induced current as a function of injected carrier generation rate, temperature and quenching excitation.