LAUSR

A triple-band infrared photodetector is developed by doping sulfur into germanium. The photocurrent spectrum at 20 K shows that there are three response bands at about 1.4, 1.6, and 6.5 µm, indicating the realization of triple-band detection. The triple response bands are attributed to the electronic transitions from the valence band to the conduction band at the Γ and L points, and from the impurity band to the conduction band, respectively. At 4 K, the overall blackbody detectivity is ~1.0 × 1011 cm Hz1/2/W. We provide a new route for realizing multiband infrared detectors.