Influence of Impact Ionization on Operation Efficiency of InN, GaN, AIN LSA-Diodes

Analyzing the results of influence of impact ionization on operation of LSA diodes, possible conclusions were listed. Described LSA diodes on the basis of InN, GaN, AIN compounds have low efficiencies and small permissible overvoltage over threshold and on these factors worst then LSA diodes on the basis of gallium arsenide. For validly of the drift approach for developing impact ionization possible excess of an electric field strength above threshold in all LSA diodes on a basis of mentioned compounds is small, the efficiencies of oscillation also is small (for InN U_max/U_cr 1,6 ... 1,9 , so efficiency is as 3 ... 6 %; for GaN U_max/U_cr 1,4 ... 1,7 at efficiency 2 ... 4 %; for AlNU_max/U_cr 1,06 ... 1,22 at efficiency 0,05 ... 0,23%). It is necessary to note, that all estimations are made for long diodes from 10 microns up to 1000 microns, on such lengths most favourably to implement LSA mode for reception of major power in cm- and mm - bands. If the impact ionization will develop in conformity with diffusion approach, performances of LSA diodes become quite comprehensible (for InN U_max/U_cr is 5 ... 5,85 at efficiency 11 ... 12%; for GaN U_max/U_cr is 4 ... 5 at efficiency 13 ... 14 %; for AIN U_max/U_cr is 2,9 ... 3,3 at efficiency 3,2 ... 3,4 %). Taking into account high frequency opportunities of the described compounds, the received results will be quite good for LSA diodes for operation in a pulsed mode. The most perspective compounds for LSA diodes from the viewed (by efficiencies of oscillation) are InN and GaN (InN is better by quantity of overvoltage on the diode, GaN by dependence V(E), it is better by efficiency of oscillation).