Research of optical properties of porous silicon derivatives

Abstract

Using electrochemical etch technology is possible to manipulate the porous silicon (por-Si) layers characteristics. We have done experimental and modelling research of the optical properties of por-Si single layers, distributed Bragg reflectors (DBR) and Fabry-Perot microcavities (FPM). Por-Si layers fabricated by electrochemical etch method have been investigated using polarization ellipsometry method. We found the accordance of the manufactured por-Si layer parameters with those taken from literature in 7% for silicon type used. The fabricated DBR and FPM demonstrate the characteristic features in reflectivity spectra. Modelling of DBR and FPM reflectivity spectra has been done to establish the optimal layer parameters ensuring their quality using the transfer matrices method. It was shown that reflectivity of integral device is sensitive to the number and porosity of the different λJ4 layers (λc- is the central wavelength). It is about 80% in the mirror of eight layers and approaches unity at15 layers. We have established the wide range of possibilities to manipulate the quality factor of the DBR and FPM by adjusting the thickness and porosity of por-Si layers as well as their number in the device.