TY - GEN N1 - Optica Applicata, Vol. 39, 2009, nr 4, s. 655-661 N2 - This paper reports on the results of optimization of ohmic contacts for GaAs/AlGaAs quantum cascade lasers (QCLs). Technological parameters during optimization concerned surface preparation, evaporation method, and thermal treatment. The aim of this research was to obtain low resistance and time stable ohmic contacts. The average specific contact resistance was 6×10–7 Ωcm–2 with record value below 3×10–7 Ωcm–2. It appears that the crucial role in contact formation is played by the in-situ surface pretreatment and thermal processing. Circular transmission line method (CTLM) was applied for electrical characterization of Ni/AuGe/Ni/Au metallization system. Secondary ion mass spectroscopy (SIMS) was used for determination of Au diffusion into semiconductor. The system presented was used in fabrication of pulse operating QCLs. The lasers mounted with diamond heat spreaders on copper block cooled by liquid nitrogen (LN) achieved optical powers over 1 W, threshold current density values of 7 kAcm–2 and differential efficiencies above 1 W/A. L1 - http://www.dbc.wroc.pl/Content/59310/optappl_3904p655.pdf M3 - artykuł L2 - http://www.dbc.wroc.pl/Content/59310 PY - 2009 KW - optyka KW - ohmic contacts KW - sputtering KW - rapid thermal annealing (RTA) KW - quantum cascade lasers (QCLs) C1 - Wszystkie prawa zastrzeżone (Copyright) A1 - Karbownik, Piotr A1 - Barańska, Anna A1 - Szerling, Anna A1 - Macherzyński, Wojciech A1 - Papis, Ewa A1 - Kosiel, Kamil A1 - Bugajski, Maciej A1 - Tłaczała, Marek A1 - Jakieła, Rafał A2 - Gaj, Miron. Redakcja A2 - Urbańczyk, Wacław. Redakcja PB - Oficyna Wydawnicza Politechniki Wrocławskiej C6 - Dla wszystkich w zakresie dozwolonego użytku LA - eng CY - Wrocław T1 - Low resistance ohmic contacts to n-GaAs for application in GaAs/AlGaAs quantum cascade lasers UR - http://www.dbc.wroc.pl/dlibra/publication/edition/59310 ER -