Progress in Understanding the Metastable Point Defects in GaAs

Semiconductor crystals are useful for technology only when they contain small and controlled amounts of point defects, i.e., atoms which are chemically wrong for the crystal or atoms which are in the wrong place. These defects can supply the electrons or holes needed to make the crystals conducting or they can serve as traps which shorten the lifetimes of the carriers. In GaAs, the DX center and EL2 are two point defects have recently been studied intensively because they are of importance to the technology of this material, and most interestingly, because they exhibit metastability which couls threaten their technological usefulness.