Author: Alois Allen Slepicka Publisher: ISBN: Category : Electronics Languages : en Pages : 78
Book Description
The Gunn effect is a recently (1963) observed phenomenon in the electrical properties of certain compound semiconductors. It is characterized by a sudden onset of oscillations in current through the material when a critical value of electric field is exceeded. The oscillations are not greatly affected by external circuit conditions, are at microwave frequencies, and occur as a bulk property at room temperature in gallium arsenide and certain other materials with the proper conduction band structure. The intervalley transfer of electrons in the conduction band from a lower energy high mobility sub-band, to a higher energy low mobility sub-band with the application of an increasing electric field gives rise to a negative differential resistance in the material. It is this mechanism which is accepted as the cause of the instabilities. A brief theoretical explanation is given. The preparation of samples of gallium arsenide is described and discussed. Sample mounting is described, and the results of various tests reported. The value of the effect lies in the ability to directly convert pulse of DC power into microwave power at usable levels and at reasonable efficiencies. (Author).
Author: Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
The Gunn effect is a recently (1963) observed phenomenon in the electrical properties of certain compound semiconductors. It is characterized by a sudden onset of oscillations in current through the material when a critical value of electric field is exceeded. The oscillations are not greatly affected by external circuit conditions, are at microwave frequencies, and occur as a bulk property at room temperature in gallium arsenide and certain other materials with the proper conduction band structure. The intervalley transfer of electrons in the conduction band from a lower energy high mobility sub-band, to a higher energy low mobility sub-band with the application of an increasing electric field gives rise to a negative differential resistance in the material. It is this mechanism which is accepted as the cause of the instabilities. A brief theoretical explanation is given. The preparation of samples of gallium arsenide is described and discussed. Sample mounting is described, and the results of various tests reported. The value of the effect lies in the ability to directly convert pulse of DC power into microwave power at usable levels and at reasonable efficiencies. (Author).
Author: J. L. Scales Publisher: ISBN: Category : Languages : en Pages : 49
Book Description
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).
Author: Michael S. Shur Publisher: Springer Science & Business Media ISBN: 1489919899 Category : Technology & Engineering Languages : en Pages : 677
Book Description
GaAs devices and integrated circuits have emerged as leading contenders for ultra-high-speed applications. This book is intended to be a reference for a rapidly growing GaAs community of researchers and graduate students. It was written over several years and parts of it were used for courses on GaAs devices and integrated circuits and on heterojunction GaAs devices developed and taught at the University of Minnesota. Many people helped me in writing this book. I would like to express my deep gratitude to Professor Lester Eastman of Cornell University, whose ideas and thoughts inspired me and helped to determine the direction of my research work for many years. I also benefited from numerous discussions with his students and associates and from the very atmosphere of the pursuit of excellence which exists in his group. I would like to thank my former and present co-workers and colleagues-Drs. Levinstein and Gelmont of the A. F. Ioffe Institute of Physics and Technology, Professor Melvin Shaw of Wayne State University, Dr. Kastalsky of Bell Communi cations, Professor Gary Robinson of Colorado State University, Professor Tony Valois, and Dr. Tim Drummond of Sandia Labs-for their contributions to our joint research and for valuable discussions. My special thanks to Professor Morko.;, for his help, his ideas, and the example set by his pioneering work. Since 1978 I have been working with engineers from Honeywell, Inc.-Drs.
Author: Alois Allen Slepicka
Author: 
Author: Communications Research Centre (Canada)
Author: Communications Research Centre (Canada)
Author: 
Author: James Susumu Takeuchi
Author: J. L. Scales
Author: 
Author: Michael S. Shur
Author: Naval Postgraduate School (U.S.)