InAs/GaAs quantum dots for THz generation

Autor:	G. Berry, Mervyn Rose, N. S. Daghestani, G. Ross, Maria Ana Cataluna
Rok vydání:	2011
Předmět:	Materials science Terahertz radiation business.industry Quantum dot Photoconductivity Energy conversion efficiency Optoelectronics Field strength Carrier lifetime Condensed Matter Physics Joule heating business Excitation
Zdroj:	physica status solidi c. 9:222-225
ISSN:	1610-1642 1862-6351
DOI:	10.1002/pssc.201100253
Popis:	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 (∼50 MV/m). The maximum estimated infrared-to-THz conversion efficiency is ∼1x10-5. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Databáze:	OpenAIRE
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