EFFECT OF ELECTRON-DOMINANT AND HOLE-DOMINANT PHOTOCURRENT ON THE MILLIMETER-WAVE PROPERTIES OF AN INDIUM-PHOSPHIDE IMPATT DIODE AT A 94 GHZ WINDOW UNDER OPTICAL ILLUMINATION

The effect of photogenerated predominant electron or hole components o f the leakage current on the admittance and negative resistance proper ties of a 94 GHz p+nn+ indium phosphide IMPATT diode under optical ill umination is presented in this paper. A computer modelling and simulat ion technique has been used to study the above effect. The results sho w that the photogenerated leakage current dominated by holes is more i mportant than that dominated by electrons in modulating the millimetre wave properties of the device and shifting its oscillation frequency. The magnitudes of electron or hole ionization rates in the semiconduc tor have been found to be correlated with the above effect.