LayTec’s ‘PearL’ measures photoluminescence spectra of CIGS thin films inline

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  PearL is an optical in-line monitoring system, measuring photoluminescence spectra of CIGS thin-film modules in production lines

LayTec launched a new in-line metrology system 'PearL' at the Intersolar Europe 2011. PearL is an optical in-line monitoring system, measuring photoluminescence spectra of CIGS thin-film modules in production lines and is part of the LayTec product line for solar applications. Photoluminescence spectra allow a fast detection of the effective Ga content of the absorber during the production process. A product option for CdTe absorbers is also available. 

Problem

Today, measurements in thin-film PV processes are mainly performed offline and not on each batch. LayTec has developed a new in-line monitoring system that is capable of measuring the properties and thickness of all layers throughout the solar cell manufacturing process. Only by such means drifts of thin-film parameters can be recognized and compensated as soon as they occur.

Solution

PearL is LayTec's advanced laser stimulated spectral photoluminescence (sPL) technology for PV absorber layer characterization and process control. Spectra are taken after each layer deposition (n and k of all materials have been determined offline beforehand). Online fitting of an optical multilayer model to the measured data gives the layer thickness of each layer. The results for the last n-1 layers are used to obtain the thickness of the n layer. Differently than integral imaging solutions (iPL), PearL delivers fast quantitative material parameters based on the spectroscopic response. In a production environment the continuous recording of the photoluminescence spectra is a highly valuable measurement for quality control.

Applications

Controlling the optical band-gap of PV absorber layers in thin-film CIGS and CdTe in industrial mass production lines. 

Platform

PearL is part of the LayTec product line for solar applications and can be combined with the industry proven LayTec SolR that delivers for all solar cell layers tight uniformity control of the film deposition process from center to edge of each thin-film module. 

Availability

June 2011 onwards.