Herrle, Thomas and Haneder, Stephan and Wegscheider, Werner (2006) Role of excited states for the material gain and threshold current density in quantum wire intersubband laser structures. Physical Review B 73, p. 205328.
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We calculated the material gain and the threshold current density for quantum wire intersubband laser structures. In quantum cascade laser devices with active regions of lower dimensionality a reduction of the non-radiative losses and consequently an increase in the material gain and a reduction of the threshold current density is predicted. In our calculations of the material gain and the threshold current density for a realistic quantum wire intersubband laser structure fabricated by the cleaved edge overgrowth (CEO) technique, however, it turns out that excited states formed in those structures even reduce the material gain compared to conventional quantum well cascade lasers. The threshold current density also turns out to be increased due to the reduced material gain on the one hand and due to a small optical confinement factor in such structures on the other hand. The main consequence for the design of such quantum wire laser structures is to avoid the formation of excited states to be able to benefit from the reduction of the dimensionality of the electron system in terms of reduced non- radiative losses.
|Institutions:||Physics > Institute of Experimental and Applied Physics > Retired Professors > Group Werner Wegscheider|
|Projects:||Graduiertenkolleg Nichtlinearität und Nichtgleichgewicht|
|Subjects:||500 Science > 530 Physics|
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Deposited On:||20 Mar 2007|
|Last Modified:||20 Jul 2011 21:02|