ABSTRACT
Elemental silicon and germanium have long been used as photodetectors. The tunability provided by SiGe and SiGeC alloys has recently been exploited for extending the range of application. The fabrication and performance of several classes of photodetector based on a heterostructure are examined in this chapter. Methods of meeting the limitations of indirect band-gap and small allowable thickness of stable strained alloy layers are described. Silicon based optical waveguides and prospects of device integration receive special emphasis.
