Heterojunctions and Metal-Semiconductor Junctions discusses semiconductor-semiconductor heterojunctions and metal-semiconductor heterojunctions, which are of significant practical importance today and also of considerable scientific interest, with worthwhile problems still to be explored and understood. Many classes of heterojunctions are believed to have new and valuable applications. Although some aspects of heterojunction behavior remain areas for continued scientific and technological study, the main outlines of the subject are clear. This book comprises nine chapters, and begins with an introduction to semiconductor heterojunctions. Succeeding chapters then discuss semiconductor p-n heterojunction models and diode behavior; heterojunction transistors; isotype (n-n, p-p) heterojunctions; optical properties of heterojunctions and heterojunction lasers; metal-semiconductor barriers; metal-semiconductor junction behavior; high yield photoemissive cathodes; and fabrication of heterojunctions. This book will be of interest to practitioners in the fields of applied physics.

The electrical and photovoltaic characteristics of Ge-GaAs and Ge-Si heterojunctions were investigated. It was found that interface states play an important role in these junctions. Theoretical estimates of the number of interface states indicate that these states have only a secondary effect on the equilibrium band diagram of Ge-GaAs junctions. This was verified by capacitance measurements. On the other hand, interface states completely dominate the band diagram of Ge-Si junctions. Tunneling and recombination currents were found to be the dominant transport mechanism in p-n Ge-GaAs and Ge-Si heterojunctions. The theoretical capacitance of abrupt heterojunctions including the effects of interface states were developed. The results show that interface effects depend on the bulk impurity concentrations and their ratio as well as the density and distribution of interface states. Good agreement was obtained between this theory and experimental results. A frequency dependent capacitance term, which is due to the rate limited charging and discharging of the interface states, was observed on several Ge-Si junctions. Photovoltaic measurements indicate that minority carriers generated in the narrow band gap material recombine at the interface. This effect usually nullifies any advantage obtained from the 'window' effect. (Author).

This report covers SERI research activities on solid-state theory, high-efficiency cells, thin-film cells, silicon purification, silicon crystallization, thick-film technology, surface and interface analysis, and growth of GaAs and related compounds by metal-organic chemical vapor desposition.