High-quality MBE growth of AlχGa1-χ As-based THz quantum cascade lasers

Tomas Roch, Aaron Andrews, Gernot Fasching 3 , Alexander Benz 3 , Werner Schrenk 1 , Karl Unterrainer 3 , and Gottfried Strasser 1
  • 1 Institut für Festkörperelektronik, Technische Universität Wien, A-1040, Vienna, Austria
  • 2 Department of Experimental Physics, FMPI, Comenius University, 842 48, Bratislava, Slovakia
  • 3 Institut für Photonik, Technische Universität Wien, A-1040, Vienna, Austria


High-quality GaAs-based quantum cascade laser (QCL) structures for the terahertz (THz) emission have been grown by solid source molecular-beam epitaxy. Ex-situ high-resolution x-ray diffraction shows that layer thickness and its control is the most critical growth aspect and that the lasing potential of the structure can be determined by the thickness accuracy of the layers. For our samples, the thickness tolerance for working lasing structures emitting approximately 100 μm was determined to be minimally above 1% for a 15 μm active region which was composed of 54.6 nm cascade cells. Increasing interface roughness adversely affects the lasing threshold and power.

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  • [1] J. Darmo, V. Tamosiunas, G. Fasching, J. Kröll, K. Unterrainer, M. Beck, M. Giovannini, J. Faist, Ch. Kremser and P. Debbage: “Imaging with a Terahertz quantum cascade laser”, Opt. Express, Vol. 12, (2004), pp. 1879–1884. http://dx.doi.org/10.1364/OPEX.12.001879

  • [2] Proceedings from Royal Society Discussion Meeting: “The teraherz gap: the generation of far-infrared radiations and its applications”, Phil. Trans. R. Soc. Lond. A, Vol. 362, (2004), pp. 197–414, full issue Number 1815 with 16 articles.

  • [3] R. Köhler, A. Tredicucci, F. Beltram, H.E. Beere, E.H. Linfield, A.G. Davies, D.A. Ritchie, R.C. Iotti and F. Rossi: “Terahertz semiconductor-heterostructure laser”, Nature, Vol. 417, (2002), pp. 156–159. http://dx.doi.org/10.1038/417156a

  • [4] H.E. Beere, J.C. Fowler, J. Alton, E.H. Linfield, D.A. Ritchie, R. Köhler, A. Tredicucci, G. Scalari, L. Ajili, J. Faist and S. Barbieri: “MBE growth of terahertz quantum cascade lasers”, J. Cryst. Growth, Vol. 278, (2005), pp. 756–764. http://dx.doi.org/10.1016/j.jcrysgro.2004.12.172

  • [5] S. Kumar, B.S. Wiliams, S. Kohen, Q. Hu and J. Reno: “Continuous-wave operation of terahertz quantum-cascade lasers above liquid-nitrogen temperature”, Appl. Phys. Lett., Vol. 84, (2004), pp. 2494–2496. http://dx.doi.org/10.1063/1.1695099

  • [6] G. Fasching, A. Benz, R. Zobl, A.M. Andrews, T. Roch, W. Schrenk, G. Strasser, V. Tamosiunas and K. Unterreainer: “Microcavity THz quantum cascade laser”, Physica E, Vol. 32, (2006), pp. 316–319. http://dx.doi.org/10.1016/j.physe.2005.12.073


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