Evaluating the Aluminum-Alloyed $\hbox{p}^{+}$-Layer of Silicon Solar Cells by Emitter Saturation Current Density and Optical Microspectroscopy Measurements

Quantification of Sheet Resistance in Boron‐Diffused Silicon Using Micro‐Photoluminescence Spectroscopy at Room Temperature

“…In recent years, with the advent of micro‐photoluminescence spectroscopy (μ‐PLS) tools, equipped with confocal optics, microstructures in Si wafers and solar cells can be investigated with very high spatial resolution, enabling the study of dislocation clusters, grain boundaries, metal and oxide precipitates, and locally laser‐doped regions . Currently, there are several μ‐PLS‐based methods to assess doping densities of heavily‐doped layers in c‐Si wafers and solar cells, proposed by different authors . Woehl et al and Gundel et al applied μ‐PLS measurements at room temperature on carefully cross‐sectioned and polished solar cell precursors to reveal the depth profile of heavily‐doped regions, based on the shift of the photoluminescence (PL) peak caused by bandgap narrowing.…”

“…Currently, there are several μ‐PLS‐based methods to assess doping densities of heavily‐doped layers in c‐Si wafers and solar cells, proposed by different authors . Woehl et al and Gundel et al applied μ‐PLS measurements at room temperature on carefully cross‐sectioned and polished solar cell precursors to reveal the depth profile of heavily‐doped regions, based on the shift of the photoluminescence (PL) peak caused by bandgap narrowing. This method is both restricted to relatively thick doped layers (tens of microns) such as aluminum‐alloyed regions and it is destructive.…”

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

“…By capturing the band‐to‐band (BB) photoluminescence signal, fundamental parameters of silicon such as the band‐to‐band absorption coefficient , radiative recombination coefficient , and temperature and doping dependencies of the silicon band gap have been determined. In addition, spectral PL methods have also been employed as a characterization tool in photovoltaics, for example to extract the diffusion length of minority carriers in silicon wafers and bricks , to quantify the light trapping capability of plasmonic structures , to examine the impacts of surface reflectance and different carrier profiles on PL spectra, or to evaluate the laser‐doped layers of silicon solar cells by applying the band‐gap‐narrowing effect in heavily‐doped silicon .…”

“…Micro‐photoluminescence spectroscopy has been applied previously on carefully cross‐sectioned and polished solar cell pre‐cursors to reveal the depth profile of highly‐doped regions, based on the shift of the PL peak caused by band‐gap narrowing. This method is restricted to relatively thick doped layers (tens of microns), such as aluminum‐alloyed regions.…”

Dislocations in laser-doped silicon detected by micro-photoluminescence spectroscopy

“…With the advantages of high spatial and spectral resolution, lPLS techniques have been utilized to pinpoint micron-scale features of defects and impurities in crystalline silicon (c-Si), such as Fe precipitates, 1 dislocations, [2][3][4][5][6] or internal stress. 7 Besides that, lPLS has been also employed to extract minority carrier lifetimes around grain boundaries in multicrystalline silicon (mc-Si) wafers, 8 to quantify doping densities in laser-doped regions, [9][10][11][12] and to detect very thin localized diffusion layers. 13 On the other hand, laser doping has been demonstrated to be an effective method to create heavily doped regions required for junction and contact formation in high efficiency silicon solar cells.…”