Metastability of defects in p-GaAs grown from a Ga-rich melt

摘要

We report the observation of metastability for defects in Si-doped p-GaAs grown from a Ga-rich melt. A configuration change occurs suddenly at a critical temperature (near 120 K) during cooldown scans, giving rise to discontinuous deep-level transient spectra. A similar phenomenon was observed on electron-irradiated float-zone-refined Si and explained in terms of entropy variations in the configurational space. We believe that the metastability found in the p-GaAs sample is also due to a barrierless transformation of defect configuration, driven by variations in both entropy and the charge state of Ga_(As).