Highly efficient solar cells with front surface texturisation

摘要

In this paper we presents a new method and technology for increasing conversion efficiency of the monocrystaline silicon solar cells, using the front surface micromachining texturisation on a 'honeycomb' pattern. The textured front surface has been obtained using a photolitographyc process to generate disc holes on the top surface, followed by isotropic etching in HNO{sub}3:HF:CH{sub}3COOH up to join together of the wells. The spectral dependence of the front surface reflection losses, has been investigated by spectrophotometric measurements. The surface reflectivity was lowered at 5%, a very good result, compared with 30% in the case of untextured monocrystalline surface. The p-n junction, made by phosphorus diffusion at ～ 0.8 μm, follows the honeycomb profile. A p+ bor diffusion was made on the back surface of the structure, in order to ensure low series resistances. The fabrication process was completed with aluminium deposition of ohmic contacts. The comparative measurements made on the solar cells with texturised surface shows an efficiency increase of more than 16% over the standard cells efficiency.