TRAPPING KINETICS AND METASTABILITY OF THE DX CENTER IN ALGAAS

Trapping characteristics of two peaks, named A and B, associated with the well-known DX center in molecular-beam epitaxial grown, silicon-doped Al xGa1-xAs (x=0.36) are studied by deep-level transient spectroscopy as function of filling pulse width. With increase in filling pulse duration, several interesting features are noted including interdependence of the two peaks apparently logarithmic increase in height, shift in the peak temperature of the low-temperature peak B, and sharp reduction in its width. These unusual features provide clues to the dynamics of carrier capture and emission at the defect. We propose a model to qualitatively explain these features.