Sn-based Ge/Ge0.975Sn0.025/Ge p-i-n photodetector operated with back-side illumination
Abstract
We report an investigation of a GeSn-based p-i-n photodetector grown on a Ge wafer that collects light signal from the back of the wafer. Temperature dependent absorption measurements performed over a wide temperature range (300 K down to 25 K) show that (a) absorption starts at the indirect bandgap of the active GeSn layer and continues up to the direct bandgap of the Ge wafer, and (b) the peak responsivity increases rapidly at first with decreasing temperature, then increases more slowly, followed by a decrease at the lower temperatures. The maximum responsivity happens at 125 K, which can easily be achieved with the use of liquid nitrogen. The temperature dependence of the photocurrent is analyzed by taking into consideration of the temperature dependence of the electron and hole mobility in the active layer, and the analysis result is in reasonable agreement with the data in the temperature regime where the rapid increase occurs. This investigation demonstrates the feasibility of a GeSn-based photodiode that can be operated with back-side illumination for applications in image sensing systems.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 11, 2016
- Source ID
- 10.1063/1.4945816
Entities
People
- ChuanâChieh Chang
- Greg Sun
- H. H. Cheng
- Huanan Li
- Richard Soref
- Steven H. Huang
Organizations
- National Science and Technology Council
- National Taiwan University
- United States Army
- University of Massachusetts Boston