Extraction of GeSn absorption coefficients from photodetector response
- Resource Type
- Conference
- Authors
- Ye, Kaiheng; Zhang, Wogong; Oehme, Michael; Schmid, Marc; Gollhofer, Martin; Kostecki, Konrad; Widmann, Daniel; Kasper, Erich; Schulze, Jorg
- Source
- 2014 7th International Silicon-Germanium Technology and Device Meeting (ISTDM) Silicon-Germanium Technology and Device Meeting (ISTDM), 2014 7th International. :137-138 Jun, 2014
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Photonics and Electrooptics
Absorption
Doping
Photodetectors
Optical variables measurement
Tin
Materials
Optical reflection
- Language
Germanium tin (GeSn) shifts the photo-response of infrared (IR) light detectors from a typical cutoff wavelength of Ge detectors of 1550nm toward the mid infrared (MIR) [1]. The determination of the optical absorption coefficient of GeSn is difficult because it requires both high grade GeSn material and appropriate measurement structure. A series of vertical pin photodetector with the absorber material GeSn of excellent quality were fabricated achieving quantitative extraction of the absorption coefficient from photo-response. In this paper the fabrication of vertical GeSn photodetectors, the measurement of the background doping level in the intrinsic region (i-region) and the determination of the absorption coefficient are presented and the influence of high doped contact layers and electro-absorption effects from the built-in electric field are discussed.