Micro-photoluminescence spectroscopy on heavily-doped layers of silicon solar cells

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We report and explain the photoluminescence spectra emitted from silicon solar cells with heavily-doped layers at the surface. A micro-photoluminescence spectroscopy system is employed to investigate the total spectrum emitted from both the heavily-doped layer and the silicon substrate with micron-scale spatial resolution. The two regions of the device give rise to separate photoluminescence peaks, due to band-gap narrowing effects in the highly-doped layer. Two key parameters, the absorption depth of the excitation wavelength, and the sample temperature, are shown to be critical to reveal the separate signatures from the two regions. Finally, this technique is applied to locally diffused and laser-doped regions on silicon solar cell pre-cursors, demonstrating the potential value of this micron-scale technique in studying and optimizing locally doped regions. (© 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) The authors report and explain the photoluminescence spectra emitted from silicon solar cells with heavily-doped layers at the surface with micron-scale spatial resolution. The two regions of the device give rise to separate photoluminescence peaks, due to band-gap narrowing effects in the highly-doped layer. This micron-scale technique demonstrates potential values in studying and optimizing locally doped regions