PHOTOELECTRIC PROPERTIES OF SI-SI1-XGEX-GE HETEROSTRUCTURES FOR INFRARED DETECTOR

Si-Si1-x Ge-x-Ge heterostructures with Ge fraction graded linearly fro m 1 to 0 have been epitaxially grown on Ge substrates by rapid thermal process/very low pressure-chemical vapor deposition. The peak value o f the spectrum response for these structures ranges from 1.3 to 1.55 m u m, which is just in accordance with the optical fiber communication window, and considered to be the superposition of the response in Si1- xGex absorption region and the Ge absorption region. High detecting se nsitivity, and low dark current have been achieved from the prototype SiGe p-type intrinsic n-type photodetectors made of these structures.