One-dimensional photonic crystal reflector using silicon-rich silicon nitride and silicon oxynitride multilayers for solar cells

Abstract

Light trapping forms an important aspect of solar cells to increase the short circuit current density, which has a direct impact on the efficiency of the solar cell. In this paper we have used a one-dimensional photonic crystal which acts as a Bragg reflector. The dielectric photonic crystal consists of 6 bilayers of silicon nitride and silicon oxynitride deposited at a low temperature of 200oC using radio frequency plasma-enhanced chemical vapor deposition. The deposition conditions of the materials used and the characterization by FTIR, XPS, Raman spectroscopy and XRD are presented. Finally, the application of this material to make a near-100% broadband reflector in the wavelength range of 800 to 1200 nm using 70 nm silicon nitride and 140 nm silicon oxynitride stacks has been demonstrated.