Modelling the Gunn Diodes Based on Variband Semiconductors;

A two-temperature model of intervalley electron transfer in the variband semiconductor is developed. This model was applied to examine the operation of the Gunn diodes based on the variband Inx(z)Ga1-x(z)As. In the active diode region the semiconductor composition x(z) is linearly coordinate-dependent. It is shown that operation of the diode with a variband active region is determined by the coordinate dependency of relaxation frequency of electron concentration in the Γ-valley of Inx(z)Ga1-x(z)As. If this frequency is a decreasing function of coordinate (in the Inx(z)Ga1-x(z)As this occurs when x(z) increases) the dipole domains propagate in the diode, while the opposite case is featured by the propagation of charged layers. The maximum output power flux ~6.5 kW/cm2 was obtained for the GaAs-In0.4Ga0.6As - diode at a frequency of 37 GHz with a 12% efficiency.