Date of Award
Doctor of Philosophy
Dr. Arthur R. McGum
Dr. Dean Halderson
Dr. Sung G. Chung
Dr. Clement Bums
The dissertation consists of two projects. In the first project, impurity modes in Photonic Crystals are studied in one- and two-dimensional Photonic Crystals. Onedimensional systems are formed from an infinite layered array of dielectric slabs and are studied for linearly polarized electromagnetic waves propagating perpendicular to the plane of slabs. Two-dimensional systems consist either of parallel cylindrical dielectric rods in vacuum or cylindrical holes containing vacuum in dielectric medium. These rods/holes are arranged in a square lattice array. The electromagnetic waves in these system propagate perpendicular to the axes of the rods and are of E or H polarization. Green’s function techniques are used to compute the impurity modes in photonic band structures. Numerical solutions are found for different types of single site and cluster impurity systems with dielectric constants appropriate to materials recently used in experimental studies on Photonic Crystals, including frequency dependent impurities, such as GaAs.
In the second project, physically based device simulation is used to study GaAs FET characteristics. A theory for the temperature dependence of the capture cross sections of deep level traps is presented. The resulting model is suitable for use in advanced semiconductor device simulators. A statistical mechanics approach is used to predict the behavior of EL2 defects in GaAs. It is also shown that the DC characteristics of GaAs MESFETs, in particular, channel confinement, can be improved by introducing buried p-layer in the device structure. The "kink" effect at high drain voltages is studied numerically. A methodology for performing accurate direct calculations of large-signal RF characteristics of power transistor and for accurate prediction of power figures-of-merit is presented. The topology of input and output matching network is studied. Harmonic loading and gate conduction effects are considered. A theory is developed for the number of RF cycles necessary to achieve periodic steady state while avoiding unwanted second harmonic tuning effects. Detailed examples of the large signal RF simulation of GaAs power MESFETs in various circuit environment and its posterior analysis are presented.
Khazhinsky, Michael G., "Study of Impurity Modes in Photonic Crystals and Study of Power GaAs MESFETS" (1997). Dissertations. 1670.