Ge1-xSnx/Ge Heterostructure Infrared Photodetector

We report the optoelectronic characterization of Ge1-xSnx/Ge heterojunction infrared (IR) photodetectors fabrication on Si substrate using rapid thermal chemical vapor deposition (RTCVD) with Ge2H6 and SnCl4 precursors and in a CMOS compatible process. We obtained that Sn contents in Ge1-xSnx epitaxial layer similar to 5.9%. The surface roughness root mean square (RMS) were 1.2 nm. The leakage current of a device as low as 0.7 mu A at 1 V and leakage current reduced as device size decrease. At 1550 nm wavelength, the responsivity of the Ge1-xSnx/Ge devices was estimated to be 54 mA/W was measured for a bias of 2 V, without an optimal antireflection coating. Fabricated device shows practicability for optoelectronic applications in the extended IR wavelength regime.