Year: 1987
Type: dissertation
Abstract: Undoped synthesized GaAs and crystals grown by the gradient freeze method were analyzed by room temperature Hall effect for net carrier concentration, secondary ion mass spectroscopy for silicon and residual impurity concentrations, localized vibrational mode spectroscopy for carbon concentration, and optical absorption for neutral EL2 concentration.Impurity compensation was examined to determine limits for silicon concentration in semi-insulating GaAs.Boules synthesized in a variety of materials are used to determine the residual impurity concentrations contributing to compensation.Shallow donor concentrations below the residual acceptor concentration resulted in semi-insulating electronic properties for two synthesis boules.The silicon incorporation rate in gradient freeze crystals is quantified through the deviation of net donor concentration from the normal freeze distribution.Crystals grown As rich, Ga rich and near stoichiometric composition in Si0 2 crucibles show order-of-magnitude differences of I would like to thank my advisor, Professor Eugene Haller for his support and encouragement throughout this work.Dr. Edith Bourret and Joseph Guitron are gratefully acknowledged for their helpful discussions, ongoing interest in this work and for the GaAs crystal growth.
Author: J. L. Hurd
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W178196768