Submillimetre performance of diode detectors using Ge, Si and GaAs

Some investigations of the characteristics of Ge, Si and GaAs point-contact diodes, and GaAs Schottky-barrier diodes, as detectors at millimetre and submillimetre wavelengths, are reported. Spectral response measurements, taken over the range of wavelengths 4 to 0·1 mm, have been obtained. The measured responses prove to be worse than those anticipated from theoretical considerations and arguments are presented in an attempt to account for the discrepancies. Of those detectors tested, the Ge point-contact diodes are the best at submillimetre wavelengths and the Schottky-barrier diodes show potential usefulness at wavelengths much shorter than those for which they have hitherto been considered.