Optical Surface Micro-structure Of Anti-reflective Properties And Optimize The Design

The microstructural surface of the optical elements have the reflective property. That is significant to reduce the reflection loss of the silicon solar cells and photoelectric detector, improve photoelectric transfer efficiency. The reflective property of mierostructure is relate to the microstructure's parameters, this paper mainly design anti-reflection structure of glass and crystalline silicon. For this purpose the subwavelength grating structure is adopted. The structure parameters which can influence the reflective property are analyzed and optimized.This paper analyzes reflective property of the glass's surface with subwavelength gratings using effective medium theory. A 1-D subwavelength grating structures and a 2-D subwavelength grating structures are obtained respectively, which are for the visible bands reflection. The 1-D structures could reduce the reflectivity to 1% when the incident angle is less than 30°; the 2-D structures could reduce the reflectivity to 1% when the incident angle is less than 50°. For the Si basement, a combined antireflective structures using SiO2 and subwavelength gratings is designed. The effective medium theory, film optical principle and material dispersion theory are using to analyse. Through numerical simulations, the parameters are got.1-D subwavelength grating and SiO2 antireflection structure is designed, its parameters:the gratings' etching depth is 0.055μm, the duty cycle is 0.55, the depth of the SiO2 is 0.1μm. This structures' weighted average reflectivity is 5.01% when the 0 and 6.25% when the incident angle is less than 60°.2-D subwavelength grating and SiO2 antireflection structure is designed, its parameters:the gratings' etching depth is 0.055μm, the duty cycle is 0.3, the depth of the SiO2 is 0.098μm. This structures' weighted average reflectivity is 2.02% when the 0 and 3% when the incident angle is less than 60°This paper designs the antireflective structures using subwavelength gratings can achieve a lower weighted average reflectivity, under the large incident angle range and the wide spectrum. It will reduce the reflection loss of the Si solar cells' surface and will enhance the efficiency of photoelectric conversion.