EN
We report on the results of experimental study of free carrier heating in degenerate GaAs tunnel p-n diodes when the carriers are excited by pulsed microwave radiation. Free carrier heating is responsible for the electromotive force in the diode. The magnitude of the electromotive force linearly depends on pulsed microwave power and increases with the decrease in semiconductor lattice temperature. It is almost independent of the pulsed microwave frequency and of p-n junction plane orientation in respect to electric field direction. In the tunnelling regime the dark current in the diode is reduced, however, at high enough forward bias the diffusive current is stimulated due to hot carrier phenomenon.