Elastic constants of porous silicon superlattices

Porous silicon superlattices with constituent layer porosities of similar to 30% and similar to 60% and modulation wavelengths of 17 nm, 20 nm and 34 nm were fabricated by electrochemical etching in HF-based electrolytes. The elastic constants of the superlattices were estimated using Brillouin light scattering spectroscopy and compared to those calculated from an effective elastic constants model (M. Grimsditch and F. Nizzoli, Phys. Rev. B 33, 5891 (1986) [1]). The fair agreement between the experimental and calculated constants suggests that the model holds promise for predicting the elastic properties of these and possibly other porous multilayered systems. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim