Because of the abrupt change of the refractive index of the contact surface of the atmosphere and silicon wafer, the reflectivity of the wafer surface after removing the mechanical damage layer is as high as 40%. Solar panel structures Reducing the reflectivity of silicon wafer and increasing optical absorption is an important direction to improve the conversion efficiency of polycrystalline silicon solar cells. The antireflection layer (such as sinx[2), which has a transitional refractive index on the surface of silicon wafer, Solar panel structures is a method which can effectively reduce the reflection, but the surface fleece is a more stable and effective method of reducing reflection. In industrialized production, monocrystalline silicon is used to reduce the reflectivity of silicon wafer surface by using anisotropic etching in alkaline solution. But polycrystalline silicon is not regular, isotropic, not in the lye, but in the acid solution of the cashmere. The reflectivity of poly-crystalline acid is about 25%, Solar panel structures and the loss of reflected light is still large.
In order to further reduce the reflectivity of polycrystalline silicon wafer surface, many kinds of methods have been tried and studied. Fabrication of nanostructures on the wafer surface effectively reduces reflectivity, and the silicon wafer looks black and is called black silicon. Terres and others used femtosecond lasers to successfully prepare the black silicon and verify that the conversion efficiency is higher than that of the amorphous silicon cells. The method of local metal catalytic wet chemical etching can also make black silicon, Solar panel structures and the battery efficiency can reach $number. Reactive ion etching (RIE) technology is widely used in the preparation of black silicon [5, 8, 9]. ZAIDI and others have shown that the short-circuit current density of a solar cell that rie and removes surface defects is higher than that produced by a wet-chemical method. Solar panel structures Lee and others have shown that the efficiency of Rie-made polycrystalline black silicon cells after the removal of surface defects is as high as 16.32%. In our previous studies, polycrystalline silica was successfully prepared by plasma immersion ion implantation (PIII) and its surface microstructure and reflectivity were studied. At present, Solar panel structures we have prepared polycrystalline silica by PIII method and studied the effect of the structure of the pile on the battery electric property.
At the same time, the reflectivity of the surface of polycrystalline silicon with acid-making is compared. It was found that the reflectivity of C1 to C5 decreased in turn. However, because of the special surface structure of black silicon (in the wavelength 300~1100nm range, the reflectivity of the C1 condition is much lower than that of the acid fleece), we can explain the effect of the black silicon with the theory of effective medium approximation. Solar panel structures The transverse size of the black Silicon Hill is about 100nm, and the reflection and diffraction of the incident light can effectively reduce the reflectivity of the wafer surface. It is clear that the small peaks increase the reflection time of the incident light on the surface of the wafer. When the size of the small peaks is close to the incident light wavelength, Solar panel structures the 0-order interference fringes weaken. Conditions C1 to C5, with the increase of the height of the small peaks, multiple reflection and interference effects will be more obvious, resulting in a lower reflectivity.