Quantum Dot Interdiffusion For Two Colour Quantum Dot Infrared Photodetectors

An investigation into the effects of thermal interdiffusion on the characteristics of quantum dot infrared photodetectors (QDIPs) yields results useful for the creation of a two-colour QDIP. For high temperature rapid thermal annealing, quantum dot interdiffusion is induced, resulting in a large wavelength redshift in the photodetector spectral response, at the cost of a small degradation in device performance. The evaluation of a two-colour QDIP fabricated using selective suppression of interdiffusion during thermal annealing shows uniform performance in the two different detector pixels. This has implications as a useful process for the future fabrication of multi-colour QDIPs

Detection wavelength tuning of InGaAs/GaAs quantum dot infrared photodetector with thermal treatment

Thermal treatment of In0.5Ga0.5As/GaAs quantum dot infrared photodetector (QDIP) structure has been carried out at 700 degrees C for 1 min with SiO2 capping layer. Thermal treatment of In0.5Ga0.5As/GaAs QDIP structure induced a blue-shift in its photoluminescence (PL) spectrum by a 50 meV with a reduction of its intensity. The blue-shift in PL spectrum and the reduction in PL intensity is thought to be due to the interdiffusion of In and Ga at the interfaces of quantum dots (QDs) and GaAs barriers. The fabricated QDIP with thermally treated structure showed a red-shift in its photocurrent spectrum by a 22 meV from the photocurrent peak of 200 meV for as-grown QDIP, as a consequence of the blue-shift of QD bandgap. (c) 2005 Elsevier Ltd. All rights reserved.X119sciescopu