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International Journal of Optics
Volume 2012, Article ID 505023, 16 pages
Review Article

Deep Level Saturation Spectroscopy

Semiconductors Physics Department Institute of Applied Research, Vilnius University, 10222 Vilnius, Lithuania

Received 31 October 2011; Revised 14 December 2011; Accepted 23 December 2011

Academic Editor: Randy A. Bartels

Copyright © 2012 Vladimir Gavryushin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We review the “Deep Level Saturation Spectroscopy” (DLSS) as the nonlinear method to study the deep local defects in semiconductors. The essence of a method is determined by the processes of sufficiently strong laser modulation (up to saturation) of quasistationar two-step absorption of the probe light via deep levels (DLs). DLSS is based on nonequilibrium processes of the optically induced population changes for deep levels which lead to the changes in an impurity absorption. This method allows us the separation of the spectral contributions from different deep centers (even in the case of their full spectral overlap), on the basis of the difference of their optical activity (photon capture cross-sections) and of their electroactivity difference (carriers capture coefficients). As shown, DLSS is allowed to determine directly the main set of phenomenological parameters (cross-sections, concentration, bound energy, etc.) for deep local defects, their content and energy position in the band gap. Some important aspects of DLSS were shown also: the possibility to connect directly the measured data to the local centers which are participating in radiative recombination, and also the possibility to study directly the phonon relaxation processes in the localized states of deep defects.