How Molecular Beam Epitaxy (MBE) Began and Its Projection into the Future

I would like to thank the committee for inviting me here to give this talk. In fact, the committee gave the title of this talk to me. Because of the limited time, my discussion will only focus on III-V compounds where as Group IV, II-VI, III-IV, metal and insulating materials by MBE will be covered by other speakers. There were many attempts to grow compound semiconductors in vacuum before the development of molecular beam epitaxy. For III-V compounds, Gunther proposed the use of a "three temperature" technique where the substrate, Group III and Group V sources had different temperatures to independently control their vapor pressures. However, he did not use single crystal substrates and, therefore, "epitaxy" could not even be defined. Later Davey and Pankey prepared epitaxial GaAs on single crystalline GaAs substrated but most of the films showed texture or twinning, and they could only report crystal structures with electron and X-ray diffractions. No transport or optical properties such as photoluminescence were reported because the films were, in general, too poor to measure.