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Textured semiconductors for enhanced photoconductive terahertz emission Collier, Christopher Michael; Krupa, Jeffrey D. A.; Hristovski, Ilija R.; Stirling, Trevor J.; Bergen, Mark; Holzman, Jonathan F.

Abstract

There are severe limitations that photoconductive (PC) terahertz (THz) antennas experience due to Joule heating and ohmic losses, which cause premature device breakdown through thermal runaway. In response, this work introduces PC THz antennas utilizing textured InP semiconductors. These textured InP semiconductors exhibit high surface recombination properties and have shortened carrier lifetimes which limit residual photocurrents in the picoseconds following THz pulse emission—ultimately reducing Joule heating and ohmic losses. Fine- and coarse-textured InP semiconductors are studied and compared to a smooth-textured InP semiconductor, which provides a baseline. The surface area ratio (measuring roughness) of the smooth-, fine-, and coarse-textured InP semiconductors is resolved through a computational analysis of SEM images and found as 1.0 ± 0.1, 2.9 ± 0.4, and 4.3 ± 0.6, respectively. The carrier lifetimes of the smooth-, fine-, and coarse-textured InP semiconductors are found as respective values of 200 ± 6, 100 ± 10, and 20 ± 3 ps when measured with a pump-probe experimental system. The emitted THz electric fields and corresponding consumption of photocurrent are measured with a THz experimental setup. The temporal and spectral responses of PC THz antennas made with each of the textured InP semiconductors are found to be similar; however, the consumption of photocurrent (relating to Joule heating and ohmic losses) is greatly diminished for the semiconductors that are textured. The findings of this work can assist in engineering of small-scale PC THz antennas for high-power operation, where they are extremely vulnerable to premature device breakdown through thermal runaway.

Item Metadata

Title
Textured semiconductors for enhanced photoconductive terahertz emission
Creator
Collier, Christopher Michael; Krupa, Jeffrey D. A.; Hristovski, Ilija R.; Stirling, Trevor J.; Bergen, Mark; Holzman, Jonathan F.
Date Issued
2016-02-25
Description
There are severe limitations that photoconductive (PC) terahertz (THz) antennas experience due to Joule heating and ohmic losses, which cause premature device breakdown through thermal runaway. In response, this work introduces PC THz antennas utilizing textured InP semiconductors. These textured InP semiconductors exhibit high surface recombination properties and have shortened carrier lifetimes which limit residual photocurrents in the picoseconds following THz pulse emission—ultimately reducing Joule heating and ohmic losses. Fine- and coarse-textured InP semiconductors are studied and compared to a smooth-textured InP semiconductor, which provides a baseline. The surface area ratio (measuring roughness) of the smooth-, fine-, and coarse-textured InP semiconductors is resolved through a computational analysis of SEM images and found as 1.0 ± 0.1, 2.9 ± 0.4, and 4.3 ± 0.6, respectively. The carrier lifetimes of the smooth-, fine-, and coarse-textured InP semiconductors are found as respective values of 200 ± 6, 100 ± 10, and 20 ± 3 ps when measured with a pump-probe experimental system. The emitted THz electric fields and corresponding consumption of photocurrent are measured with a THz experimental setup. The temporal and spectral responses of PC THz antennas made with each of the textured InP semiconductors are found to be similar; however, the consumption of photocurrent (relating to Joule heating and ohmic losses) is greatly diminished for the semiconductors that are textured. The findings of this work can assist in engineering of small-scale PC THz antennas for high-power operation, where they are extremely vulnerable to premature device breakdown through thermal runaway.
Subject
Pump-probe spectroscopy; terahertz generation; ultrafast photonics
Genre
Conference Paper
Type
Text
Language
eng
Date Available
2016-10-06
Provider
Vancouver : University of British Columbia Library
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
DOI
10.14288/1.0319017
URI
http://hdl.handle.net/2429/59381
Affiliation
Applied Science, Faculty of; Engineering, School of (Okanagan)
Citation
C. M. Collier, J. D. A. Krupa, I. R. Hristovski, T. J. Stirling, M. H. Bergen, and J. F. Holzman, "Textured semiconductors for enhanced photoconductive terahertz emission," Proceedings of SPIE Photonics West, vol. 9747, pp. 97470M(1-8), San Francisco, USA, February 13-18, 2016.
Publisher DOI
10.1117/12.2208548
Peer Review Status
Reviewed
Scholarly Level
Faculty; Researcher
Rights URI
http://creativecommons.org/licenses/by-nc-nd/4.0/
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Attribution-NonCommercial-NoDerivatives 4.0 International