Accession Number : AD0675488

Title :   COMPUTER STUDIES OF GUNN OSCILLATIONS IN GALLIUM ARSENIDE,

Corporate Author : HARRY DIAMOND LABS WASHINGTON D C

Personal Author(s) : Scales,J. L. ; Ward,A. L.

Report Date : AUG 1968

Pagination or Media Count : 49

Abstract : Gunn oscillations in gallium arsenide were simulated dynamically on a computer. By using different doping profiles, it was possible to simulate different modes of oscillation; e.g., the 'dipole' and 'charge accumulation mode.' Other space-charge configurations, which can exist in principle, would not nucleate spontaneously and repetitively in the computer simulation. The analysis was one-dimensional. The important nonlinear function expressing electron velocity as a function of electric field was assumed known in advance; no attempt was made to derive it as part of the analysis. In fact several different functions were used in order to determine what effect a change in v(E) function would have on the oscillations. The two modes mentioned above were also studied to determine the effects of changes in doping level, bias voltage, and interaction with the external circuit. With more than one nucleation center present in a sample, it was found that the center nearest the cathode tended to control the oscillation. The computer simulation gave qualitative verification to theoretical rules such as the minimum density-length product rule, and the 'equal area' rule. In addition a maximum density-length product was found for accumulation mode oscillations. Also a type of high frequency oscillation was found to occur at a voltage just below the threshold for normal dipole oscillations. (Author)

Descriptors :   (*GALLIUM ARSENIDES, MICROWAVE OSCILLATORS), MATHEMATICAL MODELS, SPACE CHARGE, SIMULATION, OSCILLATION, MATHEMATICAL ANALYSIS, DOPING

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE