High-speed planar GaAs photoconductors with surface implant layers

Selective implantation of silicon into GaAs is demonstrated as a simple method for modifying the response characteristics of low-doped planar GaAs photoconductors for optoelectronic circuits with varying requirements. Response times and sensitivities of the photoconductors were strongly dependent on the implantation dose and energy. Rise times and full width at half-maximum (FWHM) values of devices receiving low-dose implants were of the order of 40–150 ps. Rise times and FWHM values of devices which received higher dose implants were in the ranges 50–140 ps and 1–5 ns, respectively. The sensitivity of devices which received higher dose implants was about a factor of 100 (20 dB in optical power) greater than that of devices which received lower dose implants.