Improved performance of GaAs-based terahertz emitters via surface passivation and silicon nitride encapsulation

Carl Headley; Lan Fu; Patrick Parkinson; Xinlong Xu; James Lloyd-Hughes; Chennupati Jagadish; Michael B. Johnston

doi:10.1109/JSTQE.2010.2047006

Improved performance of GaAs-based terahertz emitters via surface passivation and silicon nitride encapsulation

Carl Headley^*, Lan Fu, Patrick Parkinson, Xinlong Xu, James Lloyd-Hughes, Chennupati Jagadish, Michael B. Johnston

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

30 Citations (Scopus)

Abstract

We have improved the stability and performance of terahertz (THz) photoconductive (Auston) switches using a combination of (NH₄) ₂S surface passivation (SP) and silicon nitride (Si₃ N₄) encapsulation. The influences of SP and encapsulation on the ultrafast electron dynamics in GaAs were examined using THz emission spectroscopy and optical pumpTHz probe spectroscopy. The power of THz radiation from the surface of photoexcited GaAs increased by a factor of 5 after passivation and encapsulation, while the process lengthened the trapping time for photoexcited charge carriers. By fabricating and assessing the performance of photoconductive switches, we found that passivation and encapsulation increased the average THz power generated fourfold.

Original language	English
Article number	5460898
Pages (from-to)	17-21
Number of pages	5
Journal	IEEE Journal of Selected Topics in Quantum Electronics
Volume	17
Issue number	1
DOIs	https://doi.org/10.1109/JSTQE.2010.2047006
Publication status	Published - Jan 2011

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abstract = "We have improved the stability and performance of terahertz (THz) photoconductive (Auston) switches using a combination of (NH4) 2S surface passivation (SP) and silicon nitride (Si3 N4) encapsulation. The influences of SP and encapsulation on the ultrafast electron dynamics in GaAs were examined using THz emission spectroscopy and optical pumpTHz probe spectroscopy. The power of THz radiation from the surface of photoexcited GaAs increased by a factor of 5 after passivation and encapsulation, while the process lengthened the trapping time for photoexcited charge carriers. By fabricating and assessing the performance of photoconductive switches, we found that passivation and encapsulation increased the average THz power generated fourfold.",

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AU - Lloyd-Hughes, James

AU - Jagadish, Chennupati

AU - Johnston, Michael B.

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AB - We have improved the stability and performance of terahertz (THz) photoconductive (Auston) switches using a combination of (NH4) 2S surface passivation (SP) and silicon nitride (Si3 N4) encapsulation. The influences of SP and encapsulation on the ultrafast electron dynamics in GaAs were examined using THz emission spectroscopy and optical pumpTHz probe spectroscopy. The power of THz radiation from the surface of photoexcited GaAs increased by a factor of 5 after passivation and encapsulation, while the process lengthened the trapping time for photoexcited charge carriers. By fabricating and assessing the performance of photoconductive switches, we found that passivation and encapsulation increased the average THz power generated fourfold.

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Improved performance of GaAs-based terahertz emitters via surface passivation and silicon nitride encapsulation

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