Ultrafast and Highly Sensitive Photodetectors Fabricated on High-Energy-NitrogenImplanted GaAs

192 LLE Review, Volume 95 An ion-implantation technique has been employed in the GaAs photodetector technology to obtain materials with a carrier lifetime in the picosecond and even subpicosecond regimes. Properties of proton,1 Ar+,2,3 As+,4–6 and other ion-implanted GaAs have been investigated thoroughly. Nitrogen-ion–implanted GaAs (N+-GaAs) is a relatively new member in the family of ion-implanted GaAs materials. The implantation of nitrogen into GaAs was initially done to get a diluted ternary semiconductor GaAsN. Optical properties of GaAsN, such as photoluminescence7 and N+-induced band-gap reduction,8 have been studied. It was also noted that high-energy implantation of N+ ions produced a highly resistive material after high-temperature annealing.9 The aim of this article is to present the preparation and properties of metal–semiconductor–metal (MSM) photodetectors fabricated on high-energyN+–implanted GaAs and demonstrate the performance improvement of these devices, as compared with those fabricated on low-temperature (LT)-grown GaAs.