Arsenic-implanted GaAs: An alternative material to low-temperature-grown GaAs for ultrafast optoelectronic applications

Arsenic-ion-implanted GaAs (or GaAs:As+), with excess-arsenic-related deep level defects, has recently emerged as a potential alternative to low-temperature molecular-beam-epitaxy (LTMBE) grown GaAs for ultrafast optoelectronic applications. In this paper, we review results of our structural, ultrafast optical and optoelectronic investigations of as-implanted and thermally annealed GaAs:As+. Picosecond photoconductive switching responses are reported for devices fabricated on thermally-annealed low-dose and high-dose implanted GaAs:As+. Novel sign reversals in near-bandgap ultrafast optical responses were observed and explained.