Fabrication, Characterisation, and Epitaxial Optimisation of MOVPE-Grown Resonant Tunnelling Diode THz Emitters

Razeghi, M., Baba, R., Jacobs, K. J.P., Stevens, B. J., Harrison, B. A., Mukai, T. and Hogg, R. A. (2017) Fabrication, Characterisation, and Epitaxial Optimisation of MOVPE-Grown Resonant Tunnelling Diode THz Emitters. In: SPIE OPTO 2017, San Francisco, CA, USA, 29 Jan - 02 Feb 2017, 101113A. ISBN 9781510606630 (doi:10.1117/12.2252377)

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Abstract

Resonant tunnelling diodes (RTDs) are a strong candidate for future wireless communications in the THz region, offering compact, room-temperature operation with Gb/s transfer rates. We employ the InGaAs/AlAs/InP material system, offering advantages due to high electron mobility, suitable band-offsets, and low resistance contacts. We describe an RTD emitter operating at 353GHz, radiating in this atmospheric transmittance window through a slot antenna. The fabrication scheme uses a dual-pass technique to achieve reproducible, very low resistivity, ohmic contacts, followed by accurate control of the etched device area. The top contact connects the device via the means of an air bridge. We then proceed to model ways to increase the resonator efficiency, in turn improving the radiative efficiency, by changing the epitaxial design. The optimization takes into account the accumulated stress limitations and realities of reactor growth. Due to the absence of useful in-situ monitoring in commercially-scalable metal-organic vapour phase epitaxy (MOVPE), we have developed a robust non-destructive epitaxial characterisation scheme to verify the quality of these mechanically shallow and atomically thin devices. A dummy copy of the active region element is grown to assist with low temperature photoluminescence spectroscopy (LTPL) characterisation. The resulting linewidths limits the number of possible solutions of quantum well (QW) width and depth pairs. In addition, the doping levels can be estimated with a sufficient degree of accuracy by measuring the Moss-Burstein shift of the bulk material. This analysis can then be combined with high resolution X-ray diffractometry (HRXRD) to increase its accuracy.

Item Type:Conference Proceedings
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hogg, Professor Richard and Baba, Mr Razvan
Authors: Razeghi, M., Baba, R., Jacobs, K. J.P., Stevens, B. J., Harrison, B. A., Mukai, T., and Hogg, R. A.
College/School:College of Science and Engineering > School of Engineering
College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
ISSN:0277-786X
ISBN:9781510606630
Copyright Holders:Copyright © 2017 SPIE
First Published:First published in Quantum Sensing and Nano Electronics and Photonics XIV 10111: 101113A
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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