Showing papers by "Stefan W. Glunz published in 1996"

Solar cells with efficiencies above 21% processed from Czochralski grown silicon

Abstract: Czochralski-Si (Cz-Si) of several manufacturers and with resistivities ranging from 1 to 13 /spl Omega/cm were processed into solar cells with efficiencies higher than 20% (AM1.5) using the LBSF/PERL processing sequence. The highest efficiency was 21.7%. The investigation of high efficiency Cz-Si solar cells was augmented by computer simulation and a study of the carrier lifetime before and after processing. A small degradation of solar cell performance in the lower resistivity material is discussed. Furthermore, a much simpler processing sequence is presented revealing efficiencies well above 19% on Cz-silicon and 21% on float zone-silicon.

Solar cell having an emitter provided with a surface texture and a process for the fabrication thereof

Abstract: Disclosed is a process for fabricating a solar cell as well as the solar cell itself having a grid-shaped surface texture provided with a n-doped emitter layer provided on a base material. The invention is distinguished by the fact that the base material is first covered full-surface with a n++ doping layer in the course of diffusion doping followed by a selective etching procedure on the emitter layer using a mask which produces the surface texture in such a manner that a multiplicity of crisscrossing rows of pointed ribs is created whose top section is composed of the n++ doped doping layer and bottom section of the base material.

Solar cells with mesh‐structured emitter

Abstract: The mesh-structured emitter solar cell (MESC) is introduced as a novel solar cell processing scheme. By the formation of inverted pyramids or microgrooves on a wafer with a homogeneous heavy phosphorus diffusion, a mesh of highly conducting emitter lines is formed. Using this technique, the lateral conductivity of the emitter can be increased, keeping the emitter dark saturation current at a low level. The high phosphorus surface concentration results in a low contact resistance even for screen-printed contacts. Thus, this technique is ideal for solar cells with screen-printed contacts, because the finger spacing of the front contact can be extended, resulting in smaller shadowing losses. Also the processing scheme of high-efficiency solar cells can be simplified, because the formation of the surface texturization and the locally deep diffused emitter can be combined in one step. The first cells with a mesh-structured emitter, evaporated front contacts and local ohmic rear contacts have shown efficien ies up to 21.1%. Lifetime test structures have been used to determine a low dark saturation current of 58 fA cm−2 for the mesh-structured emitter, although the structure is not yet optimized.

Solar cell with an emitter having a surface texture and process for manufacturing the same

Abstract: A process is disclosed for manufacturing a solar cell, as well as the solar cell itself provided with an n-doped emitter layer having a grid-shaped surface texture formed on a base material The invention is characterised in that the whole surface of the base material is first coated by diffusion doping with an n++ doping layer The emitter layer is then selectively etched by means of a mask that generates the surface texture A plurality of intercrossing, pointed ribs is generated whose top section consists of the n++-doped doping layer and whose bottom section consists of the base material