Preface
Semiconductor research made a giant leap forward with the invention of the transistor in 1947. Since then, a great many researchers engaged in the study of fundamental physical processes of semiconductors: mostly silicon (Si) or germanium (Ge), their growth technology, and device fabrication methods. Initially the emphasis was on the study of electronic processes with a view to optimizing the device's performance. Some efforts were made to study optical processes in semiconductors, primarily to understand the band structure of the materials. The idea to use semiconductors and their junctions for optoelectronic systems applications was not well defined in the early stages of the development of semiconductor technology.
The next decade (i.e., the 1950s) saw the emergence of Si as the leading electronic material. In fact, silicon is the material par excellence. The decade starting from 1960 marked the dominance of Si in electronics, thanks to the development of planar technology, and, later on, integrated circuits. This dominance of Si is still in force today; almost more than 95% of all electronic circuits are now grown on a Si platform. This dominance is expected to continue following the trend over the last few decades where the number of transistors in a chip doubles about every 18 months and the size of the individual transistors is shrinking at the same pace. The length of the channel in a field effect transistor has shrunk to a few tens of nanometers, and the downsizing ...
