MetastableMcenter in InP: Defect-charge-state—controlled structural relaxation

The $M$ center is an unusual metastable defect which can exist in either of two configurations, each with distinct electronic properties. These properties, together with the thermally stimulated configurational transformation kinetics, lead to a model of charge-state—controlled structural relaxation involving a shallow-donor—intrinsic-defect complex. We present studies of the electronically and optically stimulated configurational transformations. These include unique pulsed optical experiments, which are made possible by the particular properties of the defect, and which provide information on the rate of lattice relaxation associated with the transformation. The results lead to a more complete understanding of the nature of the configurational instability for the $M$ center than for any other covalent semiconductor defect exhibiting large lattice relaxation.