Picosecond InP photoconductors produced by deep implantation of heavy ions

Generation and detection of high power short optical pulses are of interest for applications such as high speed switching and optically controlled microwave generation. Such systems based entirely on semiconductor technology are highly desirable. In our experiments significant enhancement in the response of metal-semiconductor-metal photoconductive switches fabricated on Fe doped semi-insulating InP with heavy ion N+3 implantation has been observed. The response tail of the devices was effectively eliminated, resulting in FWHM pulse widths reduction from 200 ps (when unimplanted) to less than 40 ps for 4.5 micrometer gap device. No appreciable decrease in the breakdown field was observed. The dependence of spectral sensitivity on implantation dose was also studied. By proper optimization of the detector circuit, and use of high power semiconductors lasers with saturable absorber, generation of microwave signals in excess of 25 GHz and several volts could be achieved.