Advanced Concepts of Microwave Generation and Control in Solids.

Research was conducted on Gunn oscillators. Successful hybrid mode operation has been obtained over 0.75 to 5 times transit-time frequency in single diodes of epitaxial GaAs. Research was conducted on avalanche (IMPATT) diodes. The broadband negative resistance properties of a 1.3 ohm-cm, 4.5 micron N-region punch-through avalanche diode have enabled its operation as a microwave generator over a 1 to 10 GHz frequency range with 2 to 10 percent efficiency. Large-signal sample impedances were obtained for both the pure transit-time mode and the low-frequency mode was found to be characterized by the necessary presence of an idler frequency at the second harmonic. Research on gallium arsenide crystal growing is also reported. Work on the solution growth method has shown considerable promise. An elementary theory for the magnetoresistance measurement of the Hall mobility, including the correction for the finite geometry of the practical diodes, is presented, and several practical sources of measurement error are discussed. (Author)