Resonant optical microcavity based on crystalline silicon active layer

Crystalline silicon microcavities resonant at 1.1 μm were fabricated by using submicron thick Si membranes from a silicon on insulator substrate. These membranes were composed of a single crystalline Si film layered above and below two thin silicon dioxide layers. The low temperature photoluminescence (PL) of the membranes originated from the electron–hole condensed phase, which is characteristic of ultrapure crystalline silicon. The microcavities are then formed by depositing dielectric mirrors on both sides of the membranes. Optical properties of microcavities are studied by optical transmission and PL spectroscopy. The Si PL spectrum is strongly modified by the cavity: at the resonance the PL linewidth is reduced by a factor 3 and the emission is highly angle dependent.