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Proceedings Paper

AlGaAs/GaAs terahertz quantum cascade lasers with copper waveguides (Conference Presentation)

Paper Abstract

Fabrication of approx. 3 THz Al0.15Ga0.85As/GaAs QCLs grown by Molecular Beam Epitaxy equipped with Ta/Cu or Ti/Cu waveguide claddings will be presented. Our previous studies showed that copper layers as the waveguide claddings are most promising in THz QCLs technology. The theoretical predictions showed that lasers with Ti/Cu or Ta/Cu claddings (where Ti and Ta play the role of diffusion barriers and improve adhesion) show the smallest waveguide losses when compared with other metals. The main important issue of the presentation will be the wafer bonding of the QCL active region and GaAs receptor wafer. We will compare the results of ex-situ and in-situ bonding technology. The structures were tested by optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS). Our studies show that it was necessary to apply at least 5 nm-thick diffusion-barrier layers, as well as to keep all of the process temperatures below 400C in order to ensure the barrier tightness. The next important issue was control of composition of metallic claddings, in order to provide the control of the refractive index profiles of the claddings. The ridge structure lasers were fabricated with ridge width in the range 100 – 140 µm, formed by dry plasma etching in BCl3/Cl2/Ar mixture in ICP RIE system. The lasers operated with threshold current densities of approx. 1.2 kA/cm2 at 77 K and the Tmax = 130 K, when fed by 100-300 ns current pulses supplied with 0.3-1 kHz repetition frequencies. *This research is supported by The National Centre for Research and Development (bilateral cooperation, project no. 1/POLTUR-1/2016) and TUBITAK (Scientific and Technical Research Council of Turkey) project number 215E113.

Paper Details

Date Published: 8 March 2019
Proc. SPIE 10926, Quantum Sensing and Nano Electronics and Photonics XVI, 109261I (8 March 2019); doi: 10.1117/12.2510489
Show Author Affiliations
Anna Szerling, Institute of Electron Technology (Poland)
Kamil Kosiel, Institute of Electron Technology (Poland)
Piotr Prokaryn, Institute of Electron Technology (Poland)
Renata Kruszka, Institute of Electron Technology (Poland)
Jacek Ratajczak, Institute of Electron Technology (Poland)
Krystyna Golaszewska-Malec, Institute of Electron Technology (Poland)
Maciej Sakowicz, Institute of Electron Technology (Poland)
Zbig Wasilewski, Univ. of Waterloo (Canada)
Michał Szymański, Warsaw Univ. of Life Sciences-SGGW (Poland)
Maciej Kuc, Institute of Physics, Lodz Univ. of Technology (Poland)
Tomasz Czyszanowski, Institute of Physics, Lodz Univ. of Technology (Poland)
Mehtap Özdemir Köklü, Izmir Institute of Technology (Turkey)
Gülnur Aygün, Izmir Institute of Technology (Turkey)
Lütfi Özyüzer, Izmir Institute of Technology (Turkey)
Norbert Pałka, Wojskowa Akademia Techniczna im. Jaroslawa Dabrowskiego (Poland)

Published in SPIE Proceedings Vol. 10926:
Quantum Sensing and Nano Electronics and Photonics XVI
Manijeh Razeghi; Jay S. Lewis; Eric Tournié; Giti A. Khodaparast, Editor(s)

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