RAY-TRACING VS. ELECTROMAGNETIC METHODS IN THE ANALYSIS OF ANTIREFLECTIVE TEXTURED SURFACES - A FIRST APPROACH

We investigate the validity of the ray optics approach for the analysi s of antireflecting structures used in photovoltaic solar cells. The a ntireflecting structure is simulated by a periodic grating with triang ular profile and the reflected fields are calculated using two methods : one based on the ray optics approach and the other based on rigorous electromagnetic theory. As a first approach to the real problem, we c onsider a perfect conductive media. The parameter used for the charact erisation of the problem is the wavelength to period ratio lambda/d. T he theoretical analysis presented here shows important discrepancies b etween the results obtained using the ray tracing approximation and th ose obtained using a rigorous electromagnetic method, even for small v alues of lambda/d (of the order of 0.1) for which the geometrical opti cs approach is usually expected to hold.