Showing papers by "Wilhelm Warta published in 1996"
13 May 1996
TL;DR: In this paper, high efficiency Czochralski-Si solar cells with resistivities ranging from 1 to 13 /spl Omega/cm were processed into solar cells using the LBSF/PERL processing sequence.
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.
60 citations
TL;DR: The mesh-structured emitter solar cell (MESC) as mentioned in this paper was 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.
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.
15 citations
13 May 1996
TL;DR: In this article, the authors used the data of individual and connected cells to test models for multicrystalline Si solar cells, which can be used to test the performance of multi-cell Si solar cell arrays.
Abstract: Mini solar cell arrays allow all relevant solar cell parameters, including V/sub 0C/, I/sub SC/ and efficiency to be locally measured. From individual mini solar cells, larger ensembles can be constructed by means of parallel connection. The data of individual and connected cells can be used to test models for multicrystalline Si solar cells.
7 citations