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.