Epitaxial SiGeC waveguide photodetector grown on Si substrate with response in the 1.3-1.55-mu m wavelength range

A Si-based waveguide photodetector with a response in the 1.3-1.55-mu m wavelength range is demonstrated. The active absorption layer of the pin photodiode consists of a SiGeC allov epitaxially grown on a Si substrate with a Ge content of 55% and a thickness of 800 Angstrom. The external quantum efficiency for a 400-mu m-long waveguide, measured by using a single-mode fiber coupled to the waveguide facet, is 0.2% at 1.55 mu m. The dark current density at peak photoresponse is 40 pA/mu m(2). The quantum efficiency can be further enhanced hy using multiple SiGeC layers as the absorber, Direct measurements of the absorption coefficient for the alloy layer are also reported.