Tailoring the optical properties of silicon nanowire arrays through strain

A unique supercritical fluid inclusion-phase technique has been developed to embed silicon nanowires, with size monodispersed diameters, within the pores of mesoporous silica hosts. These nanocomposite materials displayed quite intense room temperature ultraviolet and visible photoluminescence (PL), and the emission wavelength maximum was found to be dependent on the diameter of the encased nanowires. This previously unobserved wavelength dependence of the ultraviolet PL with decreasing nanowire size is explained using a continuum strain model resulting from confinement of the wires within the host lattice.