CATHODOLUMINESCENCE STUDY OF THE SPATIAL-DISTRIBUTION OF ELECTRON-HOLE PAIRS GENERATED BY AN ELECTRON-BEAM IN AL0.4GA0.6AS

We use the cathodoluminescence mode of a scanning electron microscope to investigate the depth and lateral dependencies of the electron-hole pairs generation by the electron beam in Al0.4Ga0.6As semiconducting material. A multiquantum well structure acts as a detector to measure the relative number of generated minority carriers by their radiative recombination, allowing a direct assessment of the generation volume i n the sample. In contrast to electron-beam induced current which was u sed in former studies, the method avoids the effect of carrier diffusi on for direct band gap materials. This novel technique can be readily applied to other III-V and II-VI semiconductors. The results may be us ed for the quantitative interpretation of cathodoluminescence and elec tron-beam induced current measurements. (C) 1996 American Institute of Physics.