Photoconductive detection of millimetre waves using proton bombarded GaAs

We show that ion-damaged GaAs may be used to detect millimetre electromagnetic waves in photoconductive sampling gates. The semi-insulating GaAs material which was implanted with a dose of 10/sup 14/ cm/sup -2/ protons at an energy of 200 keV gave a signal to noise improvement of about 11.4 dB when compared with as-grown semi-insulating GaAs. The improvement is in spite of reduced carrier mobility in the ion-implanted material and is due to the shorter carrier lifetime and formation of Ohmic contacts with the ion-damaged semi-insulating GaAs.