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InAs/GaAs quantum dots for THz generation

InAs/GaAs quantum dots for THz generation

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Original languageEnglish
Pages222-225
Number of pages4
JournalPhysica Status Solidi C: Current Topics in Solid State Physics
Journal publication date2012
Journal number2
Volume9
DOIs
StatePublished

Abstract

We report pulsed terahertz generation from InAs/GaAs quantum-dot based photoconductive devices. For 800 nm optical excitation, the dots act as recombination centres for carriers generated in the GaAs layers. Using photoreflective pump-probe measurements we demonstrate that the photogenerated carrier lifetime decreases when a lateral bias is applied. This can be attributed to an increase in the capture area of the dots when under bias. Two types of antenna metallization were investigated; non-Ohmic, and quasi-Ohmic contacts. Non-Ohmic antennae displayed resilience to Joule heating when operated at a field strength of 46 MV/m. The breakdown field of the devices was 48 MV/m, which is comparable to the breakdown field of bulk GaAs (similar to 50 MV/m). The maximum estimated infrared-to-THz conversion efficiency is similar to 1x10(-5). (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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