Two-color InGaAs/GaAs quantum dot infrared photodetectors by selective area interdiffusion

We report the postgrowth fabrication of two-color InGaAs/GaAs quantum dot infrared photodetectors (QDIPs). By capping half of the as-grown QDIP structure with titanium dioxide (TiO(2)) and performing rapid thermal annealing under the optimized condition, a blueshifted photoluminescence from the uncapped region was obtained compared with the TiO(2) covered region. The corresponding device spectral photoresponse from the two adjacent regions exhibited a shift of 0.8 mu m around the wavelength of 6 mu m. This is a result of the simultaneous promotion and suppression of thermal interdiffusion during rapid thermal annealing. (C) 2008 American Institute of Physics.