Research of optical diffraction properties on surface pit array light-trapping structure

Abstract

Pit array structure has a good light-trapping characteristic, which can effectively reduce the surface light reflection and prolong the optical path. Therefore in the photo voltaic field, especially in the thin film silicon solar cells field, the pit array structure has good prospects. In this paper, a combining method of theory analysis and experimental verification was used to research the optical diffraction characterizes of the surface pit array light-trapping structure, and the effect of diffraction on the absorption characteristics of silicon thin-film solar cells was discussed. The results show that the greater the aspect ratio of the pit arrays, the better effect of the diffraction, which is more advantageous for uniform scattering of light, and more contribution to the absorption of the incident light and the improvement of the efficiency for the solar cells. Another, the diffraction characteristics of the pit structure are also related to the wavelength of the incident wave. The longer the incident wavelength is, the better the diffraction effect is. This paper research is of important reference value for the design of high-efficiency light-trapping arrays and diffraction grating.