Thermo–optic coefficient of porous silicon
Abstract
Thermo-optic coefficients of porous silicon having the same thickness but different porosities have been calculated. Boron-doped silicon substrates have been electrochemically etched in a 12% HF solution at current densities 2.5mA/cm2 and 15mA/cm2 to fabricate ~1μm thick porous silicon. Temperature-dependent reflectance spectroscopy was performed to calculate the refractive index, porosity, and thermo-optic coefficient of the samples. Using the Bruggeman effective medium approximation formula, the calculated porosities of the samples were found to be 66.37% and 77.29% respectively. In the temperature range of 303.15K–484.15K, thermo-optic coefficients of -4.0x10-4K-1 and -3.0x10-4K-1 were obtained. Simulation data was also obtained using a Sellmeier fit to verify the reflectance spectra of porous silicon.
