Analysis of temperature dependence of Ge-on-Si p-i-n photodetectors

We investigate the temperature dependence of p-i-n photodetectors realized in germanium on silicon. The dark current increases by a factor 1.6-1.9 every 10 degrees C and is typically dominated by generation in the space charge region, with diffusion contributing in the best samples. The near infrared (NIR) responsivity decreases with temperature in devices with a large defect-density, but is more stable in high-quality photodiodes. These findings provide a relevant insight on the design of Ge-on-Si NIR detectors to be operated above room temperature. (C) 2008 Elsevier B.V. All rights reserved.