Enhanced terahertz radiation of photoconductive antenna fabricated on GaAs-on-sapphire

Jitao Zhang, Mingguang Tuo, Michael Gehl, Ricky Gibson, Min Liang, Hao Xin

Research output: Contribution to journalArticle

Abstract

The terahertz (THz) radiation properties of a photoconductive antenna (PCA) fabricated on a GaAs-on-sapphire (GoS) substrate are reported at sub-THz band. The GaAs layer with a thickness of approximately 1 μm was directly deposited on a sapphire wafer by means of molecular beam epitaxy. A butterfly-shaped antenna structure was then fabricated on the GoS substrate by photolithography, and the device was tested as the emitter of an in-house built THz time-domain spectrometer. The performance of this antenna was compared with a commercial one, which had an identical antenna structure but was fabricated on low-temperature-grown GaAs (LT-GaAs). The results showed that the GoS-based PCA radiated an enhanced THz field, which could be as much as 1.9 times that of the LT-GaAs-based PCA, indicating that GoS could be a promising photoconductive material. In addition, the optical transparency of the sapphire substrate allows the device to be illuminated from the backside, which is crucial for THz near-field imaging applications where the sample is usually in close proximity to the front surface of the PCA device.

Original languageEnglish (US)
Article number125234
JournalAIP Advances
Volume9
Issue number12
DOIs
StatePublished - Dec 1 2019

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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