Abstract

Bulk crystalline silicon (Si) and germanium (Ge) are the two most important indirect bandgap semiconductors. Bulk Si crystal is the main material of today’s microelectronic/nanoelectronic, photovoltaic, and microelectromechanical system (MEMS) technologies. In particular, the ubiquitous “Si chip” is taken for granted in today’s society. Germanium is a semiconductor material that formed the basis for the development of transistor technology (the first solid-state transistor was made with Ge). But by the late 1950s, silicon had emerged as the favored semiconductor, and it has remained ever since because of the breakthrough of planar technology and integrated circuit (IC) technology. Nevertheless, Ge is an important material for optoelectronic devices such as photodetectors and solar cells, and in recent years there has been renewed interest in Ge, which has been triggered by its strong potential for deep submicrometer (sub-45 nm) IC technologies.