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Photo-Conductive Detection of Continuous THz Waves Via Manipulated Ultrafast Process in Nanostructures
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- Authors
- Kiwon Moon, Eui Su Lee, Il-Min Lee, Dong Woo Park, Kyung Hyun Park
- Issue Date
- 2018-01
- Citation
- Applied Physics Letters, v.112, no.3, pp.1-5
- ISSN
- 0003-6951
- Publisher
- American Institute of Physics (AIP)
- Language
- English
- Type
- Journal Article
- Abstract
- Time-domain and frequency-domain terahertz (THz) spectroscopy systems often use materials fabricated with exotic and expensive methods that intentionally introduce defects to meet short carrier lifetime requirements. In this study, we demonstrate the development of a nano-photomixer that meets response speed requirements without using defect-incorporated, low-temperature-grown (LTG) semiconductors. Instead, we utilized a thin InGaAs layer grown on a semi-insulating InP substrate by metal-organic chemical vapor deposition (MOCVD) combined with nano-electrodes to manipulate local ultrafast photo-carrier dynamics via a carefully designed field-enhancement and plasmon effect. The developed nano-structured photomixer can detect continuous-wave THz radiation up to a frequency of 2 THz with a peak carrier collection efficiency of 5%, which is approximately 10 times better than the reference efficiency of 0.4%. The better efficiency results from the high carrier mobility of the MOCVD-grown InGaAs thin layer with the coincidence of near-field and plasmon-field distributions in the nano-structure. Our result not only provides a generally applicable methodology for manipulating ultrafast carrier dynamics by means of nano-photonic techniques to break the trade-off relation between the carrier lifetime and mobility in typical LTG semiconductors but also contributes to mass-producible photo-conductive THz detectors to facilitate the widespread application of THz technology.
- KSP Keywords
- Collection efficiency, InP substrate, Low temperature(LT), Metalorganic chemical vapor deposition, Nano-electrodes, Nano-structured, Photo-carrier, Photo-conductive, Semi-Insulating, THz detectors, THz radiation