All-optical multiwavelength technique for the simultaneous measurement of bulk recombination lifetimes and front/rear surface recombination velocity in single crystal silicon samples

In this article, a contactless, all-optical, nondestructive method for separating the minority carrier recombination lifetime and surface recombination velocities in silicon samples at a low injection level is presented. The technique can be described as a pump-probe method in which the excess carrier density is probed by analyzing the free carrier absorption transient following laser pulse excitation that have several wavelengths. An attractive characteristic of the proposed technique is its capability to measure different values of surface recombination velocity on front and back surfaces of the silicon sample. The theoretical foundation of the method is also analyzed. Moreover, numerical simulations which validate the proposed methodology and preliminary experimental results that prove the applicability of scheme are presented.