Fine structures of Fe-related deep levels in GaAsP

The capacitance transients caused by hole emissions from Fe-related deep le vels were measured in GaAs and GaAs0.77P0.23 at different temperatures Non- exponential transients were investigated under different conditions and fou nd to relate to the alloy random effect. The transients were decomposed usi ng a Laplace defect spectroscope (LDS). The three well-resolved sharp peaks in the LDS spectra of GaAs0.77P0.23 were assigned to the fine structures o f the Fe-related deep levels. The activation energy differences of the fine structures were determined by linear fitting of the slopes of temperature dependences of hole emission rates. The results suggest that the local comp osition fluctuation in the nearest neighbors of Fe atoms is likely to be re sponsible for the fine structures.