We report a metal-Ge-metal photodetector fabricated on a Ge epitaxial layer grown on Si (100) substrate. Amorphous Ge was used to increase the Schottky barrier height, which resulted in a reduction of the dark current by more than two orders of magnitude. The dark current measured on a photodetector having 1 μm finger width and 2 μm spacing with 25 × 50 μm 2 active area was 7.5 μA at 3 V. At the wavelength of 1.3 μm, the external quantum efficiency was 14.3% (0.15 A/W) without an antireflecting coating. At reverse biases of 1, 2, 3, and 4 V, the 3-dB bandwidth was found to be 1.5,2.8,3.1, and 4.3 GHz, respectively.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering