Observations were made of the metastability of defects in Si-doped p-GaAs which was grown from a Ga-rich melt. It was found that a configuration change occurred suddenly, at a critical temperature near to 120K, during cool-down scans. This gave rise to discontinuous deep-level transient spectra. A similar phenomenon was observed in electron-irradiated float-zone Si, and was explained in terms of entropy variations in configuration space. It was suggested that the metastability found in p-type GaAs samples was also due to a barrierless transformation, in defect configuration, which was driven by variations in both the entropy and the charge state of GaAs.

Metastability of Defects in p-GaAs Grown from a Ga-Rich Melt. Z.Q.Fang, J.W.Kim, P.W.Yu: Applied Physics Letters, 2001, 78[17], 2506-8