Broadband InGaAs-capped InAs/GaAs quantum-dot infrared photodetector with Bi-modal dot height distributions

Abstract

The influence of quantum-dot (QD) height distribution on the detection wavelengths of InGaAs-capped quantum-dot infrared photodetectors (QDIPs) is investigated. For devices with 2.8 and 2.0 mono-layer (ML) InAs coverage, 7.6 and 10.4 mu m detection wavelengths are observed. The results suggest that reduced dot height would result in a longer detection wavelength. By using 2.4 ML InAs QDs with bi-modal dot height distributions, a 6-12 mu m broadband QDIP is achieved with the combination of similar to 8 and similar to 10 mu m peak detection wavelengths contributed by the larger and smaller InAs QDs. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745052]