Theory of the metastable injection-bleached E3c center in GaAs

The E3 transition in irradiated GaAs observed in deep level transient spectroscopy (DLTS) was recently discovered in Laplace-DLTS to encompass three distinct components. The component designated E3c was found to be metastable, reversibly bleached under minority carrier (hole) injection, with an introduction rate dependent upon Si doping density. It is shown through first-principles modeling that the E3c must be the intimate Sivacancy pair, best described as a Si sitting in a divacancy Sivv. The bleached metastable state is enabled by a doubly site-shifting mechanism: Upon recharging, the defect undergoes a second site shift rather returning to its original E3c-active configuration via reversing the first site shift. Identification of this defect offers insights into the short-time annealing kinetics in irradiated GaAs.

Automated summary

The E3 transition in irradiated GaAs has been observed to have three distinct components in deep level transient spectroscopy (DLTS). The component designated E3c is found to be metastable, reversible bleaching under minority carrier injection, with an introduction rate depending on Si doping density. First-principles modeling reveals that E3c must be the intimate Sivacancy pair, best described as a Si sitting in a divacancy Sivv. The bleached metastable state is enabled by a doubly site-shifting mechanism, where the defect undergoes a second site shift upon recharging rather than returning to its original E3c-active configuration by reversing the first site shift. Identifying this defect provides insights into short-time annealing kinetics in irradiated GaAs.