Separation of bulk lifetime and surface recombination velocity obtained by transverse optical probing and multi-wavelength technique

In this paper, a contactless, all-optical and non-destructive technique for simultaneous measurement of minority carrier recombination lifetime and Surface recombination velocity is presented. The principle is based upon measurement, at low injection level, of the free carrier optical absorption transient probed by an infrared beam following electron-hole pairs excitation by a pulsed laser beam working at several wavelengths. Being contactless and nondestructive with respect to the surface to be analyzed, the method is appealing for routine lifetime characterization. A brief review of the theory underlying the measurement technique, aimed to emphasize its advantages and limits, and preliminary experimental data proving the applicability of the new scheme are presented. (C) 2002 Elsevier Science Ltd. All rights reserved.