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Thursday, March 26, 2015
Abstract-Processing of AlGaAs/GaAs quantum-cascade structures for terahertz laser
Anna Szerling, Kamil Kosiel, Krystyna Gołaszewska, Adam Łaszcz, Mariusz Płuska, Artur Trajnerowicz, Maciej Sakowicz, Anna Piotrowska
Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw, Poland
Warsaw University of Life Sciences, Faculty of Applied Informatics and Mathematics, Nowoursynowska 159, 02-776 Warsaw, Poland
University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
Michał Walczakowski, Norbert Pałka
Military University of Technology, Kaliskiego 2, 00-908 Warsaw, Poland
Institute of Physics PAS, Al. Lotników 32/46, 02-668 Warsaw, Poland
J. Nanophoton. 9(1), 093079 (Mar 24, 2015). doi:10.1117/1.JNP.9.093079
Abstract. We report research results with regard to AlGaAs/GaAs structure processing for THz quantum-cascade lasers (QCLs). We focus on the processes of Ti/Au cladding fabrication for metal–metal waveguides and wafer bonding with indium solder. Particular emphasis is placed on optimization of technological parameters for the said processes that result in working devices. A wide range of technological parameters was studied using test structures and the analysis of their electrical, optical, chemical, and mechanical properties performed by electron microscopic techniques, energy dispersive x-ray spectrometry, secondary ion mass spectroscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, and circular transmission line method. On that basis, a set of technological parameters was selected for the fabrication of devices lasing at a maximum temperature of 130 K from AlGaAs/GaAs structures grown by means of molecular beam epitaxy. Their resulting threshold-current densities were on a level of 1.5kA/cm2. Furthermore, initial stage research regarding fabrication of Cu-based claddings is reported as these are theoretically more promising than the Au-based ones with regard to low-loss waveguide fabrication for THz QCLs.