Investigation of the possibility of implementing a mid-frequency broadband swept-frequency generator based on the structure of semi-insulating gallium arsenide

Background and Objectives: In previous works, the authors of the article reported on the prospects of creating the functional microelectronic devices with wide functionality based on the semi-insulating gallium arsenide (GaAs) structures provided that they exhibit Gunn or recombination current instabilities. The aim of the work is to obtain a current oscillation frequency sweep based on the recombination current instability in semi-insulating gallium arsenide that occurs in strong electric fields. Materials and Methods: Experimental samples made by the basis of industrial GaAs epitaxial wafers. The cathode contact of the sample is a mesa structure, and the anode contact is a pressure point contact. The output signal of the sample is a voltage oscillation across the load resistor. The current oscillations frequency depends on the value of the power of the incident optical radiation in the visible or infrared ranges of the spectrum. The oscillations were caused by the recombination current instability in semi-insulating gallium arsenide in high electric fields. Results: When the current on the laser diode illuminating the surface of the sample has a sawtooth shape, a sweeping of the frequency of the sample’s output signal has been observed. The dependence of the frequency versus the lighting intensity contains a linear section within which the frequency change factor reaches 1.6 times, the frequency sweeping band is significantly greater than 1% of the maximum frequency of the operating range, and the amplitude of the generated signal changes by no more than 6%. Conclusion: The fundamental possibility of obtaining current oscillation frequency sweeps in the range of low, medium and high frequencies based on the recombination current instability in semi-insulating GaAs has been demonstrated. Thus, it can be argued that it is possible to create a primary generator as part of a sweep generator based on the proposed principle.

swept-frequency generator, semi-insulating gallium arsenide, recombination current instability