MECHANISM OF FREQUENCY-CONVERSION IN AN N-TYPE INSB MIXER

A comprehensive investigation was made of an n-type InSb mixer operating at lambda = 2.6 mm. The current-voltage characteristics were recorded in a field E = 0.2 V/cm, the temperature dependence of the conductivity was determined in the range T = 1.6-20 K, the hf conductivity was measured at frequencies f = 0.5-10 MHz, and the magnetoresistance was determined in fields H = 0-5 kOe. Under optimal conditions the mechanism of frequency conversion was related to photoionization processes involving hopping photoconductivity. A hopping photoconductivity model was used to calculate the conversion efficiency of the mixer and the results were compared with the experimental data. It was found that a model of frequency conversion in compensated n -type InSb (with the compensation ratio K greater-than-or-equal-to 0.8) based on electron heating was unsatisfactory. The requirements in respect of the parameters of the material and in respect of the conditions of operation of an n-type InSb mixer in the millimeter wavelength range were analyzed.