Micro-Photoluminescence Characterisation of Structural Disorder in Resonant Tunneling Diodes for THz Applications

Cito, M., Baba, R. , Childs, D. , Harrison, B.A., Watt, A., Mukai, T. and Hogg, R. A. (2021) Micro-Photoluminescence Characterisation of Structural Disorder in Resonant Tunneling Diodes for THz Applications. In: SPIE Nanoscience + Engineering, San Diego, California, United States, 1-5 August 2021, ISBN 9781510644397 (doi: 10.1117/12.2594685)

Abstract

We investigated the difference between a macro scale PL and μPL (excitation and detection area ≤ 5μm2). Low-temperature micro-photoluminescence (μPL) is used to evaluate structural perfection of high current density InGaAs/AlAs/InP resonant tunnelling diodes (RTD) structure on different length scales. The thin and highly strained quantum wells (QWs) is subject to monolayer fluctuations in well and barrier thickness that can lead to random fluctuations in their band profile. μPL is performed reducing the laser spot size using a common photolithography mask to reach typical RTD mesa size (a few square microns). We observed that for spot size around 1μm2 the PL line shape present strong differences on multiple points on the wafer. These variations in the PL is investigated by line-shape fitting and discussed in terms of variations in long-range disorder brought about by strain relaxation processes. We also highlight this μPL as a powerful and cost-effective non-destructive characterization method for RTD structures.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cito, Mr Michele and Baba, Mr Razvan and Hogg, Professor Richard and Childs, Dr David and Watt, Adam
• Authors: Cito, M., Baba, R., Childs, D., Harrison, B.A., Watt, A., Mukai, T., and Hogg, R. A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• ISSN: 1996-756X
• ISBN: 9781510644397
• Copyright Holders: Copyright © 2021 SPIE
• Publisher Policy: Reproduced in accordance with the publisher copyright policy