Splitting of porous silicon microcavity mode due to the interaction with Si-H vibrations

A Fabry-Perot microcavity centred in the infrared around 2000-2200 cm(-1) has been realised by controlling the current and the time of a steps anodization procedure of a p(+) type silicon wafer in an electrochemical cell with a hydrofluoric acid solution. The interaction of the cavity mode, detectable as a sharp deep in the high reflectivity plateau, with the Si-H vibration modes gives rise to a splitting of the cavity mode dispersion curve (frequency vs wavevector) and to an enhancement of the infrared absorption of the Si-H bands. Both, the dispersion of the coupled modes (cavity/Si-H modes) and their infrared absorption enhancement have been studied. (C) 1998 Elsevier Science S.A. All rights reserved.