Abstract: Methods and apparatus are presented for measuring a photoluminescence (PL) response, preferably a spatially resolved image of a PL response, from an object exposed to solar irradiation. In certain embodiments signals from the object are measured in two or more different spectral bands selected such that one of the measured signals has a higher PL component relative to ambient reflectance compared to another measured signal, enabling the PL component to be enhanced by a suitable differencing procedure. In other embodiments a signal from an object is measured in a spectral band selected such that at least 20% of the measured signal comprises PL generated from the object by the solar irradiation. The methods and apparatus have particular application to outdoor inspection of photovoltaic modules without having to modulate the operating point of the modules.

Abstract: Methods and systems are presented for analysing semiconductor materials as they progress along a production line, using photoluminescence images acquired using line-scanning techniques. The photoluminescence images can be analysed to obtain spatially resolved information on one or more properties of said material, such as lateral charge carrier transport, defects and the presence of cracks. In one preferred embodiment the methods and systems are used to obtain series resistance images of silicon photovoltaic cells without making electrical contact with the sample cell.

Abstract: Methods and systems are presented for analysing semiconductor materials as they progress along a production line, using photoluminescence images acquired using line-scanning techniques. The photoluminescence images can be analysed to obtain spatially resolved information on one or more properties of said material, such as lateral charge carrier transport, defects and the presence of cracks. In one preferred embodiment the methods and systems are used to obtain series resistance images of silicon photovoltaic cells without making electrical contact with the sample cell.

Abstract: Methods and systems are presented for analyzing semiconductor materials as they progress along a production line, using photoluminescence images acquired using line-scanning techniques. The photoluminescence images can be analyzed to obtain spatially resolved information on one or more properties of said material, such as lateral charge carrier transport, defects and the presence of cracks. In one preferred embodiment the methods and systems are used to obtain series resistance images of silicon photovoltaic cells without making electrical contact with the sample cell.

Abstract: Some examples include determining the condition of photovoltaic modules at one or more points in time, in particular using line-scanning luminescence imaging techniques. One or more photoluminescence and/or electroluminescence images of a module may be acquired and processed using one or more algorithms to provide module data, including the detection of defects that may cause or may have caused module failure. Additionally, some examples include determining the condition of photovoltaic modules, such as throughout the production, transport, installation and service life of the photovoltaic modules.

Abstract: Some examples include determining the condition of photovoltaic modules at one or more points in time, in particular using line-scanning luminescence imaging techniques. One or more photoluminescence and/or electroluminescence images of a module may be acquired and processed using one or more algorithms to provide module data, including the detection of defects that may cause or may have caused module failure. Additionally, some examples include determining the condition of photovoltaic modules, such as throughout the production, transport, installation and service life of the photovoltaic modules.

Abstract: Methods and systems are presented for analysing semiconductor materials as they progress along a production line, using photoluminescence images acquired using line-scanning techniques. The photoluminescence images can be analysed to obtain spatially resolved information on one or more properties of said material, such as lateral charge carrier transport, defects and the presence of cracks. In one preferred embodiment the methods and systems are used to obtain series resistance images of silicon photovoltaic cells without making electrical contact with the sample cell.

Abstract: Methods (600) and systems (100) for inspecting an indirect bandgap semiconductor structure (140) are described. A light source (110) generates light (612) suitable for inducing photoluminescence in the indirect bandgap semiconductor structure (140). A short-pass filter unit (114) reduces long-wavelength light of the generated light above a specified emission peak. A collimator (112) collimates (616) the light. A large area of the indirect bandgap semiconductor structure (140) is substantially uniformly and simultaneously illuminated (618) with the collimated, short-pass filtered light. An image capture device (130) captures (620) images of photoluminescence simultaneously induced by the substantially uniform, simultaneous illumination incident across the large area for the indirect bandgap semiconductor structure.

Abstract: Embodiments of methods and systems for identifying or determining spatially resolved properties in indirect bandgap semiconductor devices such as solar cells are described. In one embodiment, spatially resolved properties of an indirect bandgap semiconductor device are determined by externally exciting the indirect bandgap semiconductor device to cause the indirect bandgap semiconductor device to emit luminescence (110), capturing images of luminescence emitted from the indirect bandgap semiconductor device in response to the external excitation (120), and determining spatially resolved properties of the indirect bandgap semiconductor device based on a comparison of relative intensities of regions in one or more of the luminescence images (130).

Abstract: Methods and systems are presented for analyzing semiconductor materials as they progress along a production line, using photoluminescence images acquired using line-scanning techniques. The photoluminescence images can be analyzed to obtain spatially resolved information on one or more properties of said material, such as lateral charge carrier transport, defects and the presence of cracks. In one preferred embodiment the methods and systems are used to obtain series resistance images of silicon photovoltaic cells without making electrical contact with the sample cell.

Abstract: Embodiments of methods and systems for identifying or determining spatially resolved properties in indirect bandgap semiconductor devices such as solar cells are described. In one embodiment, spatially resolved properties of an indirect bandgap semiconductor device are determined by externally exciting the indirect bandgap semiconductor device to cause the indirect bandgap semiconductor device to emit luminescence (110), capturing images of luminescence emitted from the indirect bandgap semiconductor device in response to the external excitation (120), and determining spatially resolved properties of the indirect bandgap semiconductor device based on a comparison of relative intensities of regions in one or more of the luminescence images (130).

Abstract: A method is disclosed whereby luminescence images are captured from as-cut or partially processed bandgap materials such as multicrystalline silicon wafers. These images are then processed to provide information about defects such as dislocations within the bandgap material. The resultant information is then utilized to predict various key parameters of a solar cell manufactured from the bandgap material, such as open circuit voltage and short circuit current. The information may also be utilized to apply a classification to the bandgap material. The methods can also be used to adjust or assess the effect of additional processing steps, such as annealing, intended to reduce the density of defects in the bandgap materials.

Abstract: Embodiments of methods and systems for identifying or determining spatially resolved properties in indirect bandgap semiconductor devices such as solar cells are described. In one embodiment, spatially resolved properties of an indirect bandgap semiconductor device are determined by externally exciting the indirect bandgap semiconductor device to cause the indirect bandgap semiconductor device to emit luminescence (110), capturing images of luminescence emitted from the indirect bandgap semiconductor device in response to the external excitation (120), and determining spatially resolved properties of the indirect bandgap semiconductor device based on a comparison of relative intensities of regions in one or more of the luminescence images (130).

Abstract: Methods (600) and systems (100) for inspecting an indirect bandgap semiconductor structure (140) are described. A light source (110) generates light (612) suitable for inducing photoluminescence in the indirect bandgap semiconductor structure (140). A short-pass filter unit (114) reduces long-wavelength light of the generated light above a specified emission peak. A collimator (112) collimates (616) the light. A large area of the indirect bandgap semiconductor structure (140) is substantially uniformly and simultaneously illuminated (618) with the collimated, short-pass filtered light. An image capture device (130) captures (620) images of photoluminescence simultaneously induced by the substantially uniform, simultaneous illumination incident across the large area for the indirect bandgap semiconductor structure.

Abstract: Methods are presented for separating the effects of background doping density and effective minority carrier lifetime on photoluminescence (PL) generated from semiconductor materials. In one embodiment the background doping density is measured by another technique, enabling PL measurements to be analysed in terms of effective minority carrier lifetime. In another embodiment the effective lifetime is measured by another technique, enabling PL measurements to be analysed in terms of background doping density. In another embodiment, the effect of background doping density is removed by calculating intensity ratios of two PL measurements obtained in different spectral regions, or generated by different excitation wavelengths. The methods are particularly useful for bulk samples such as bricks or ingots of silicon, where information can be obtained over a much wider range of bulk lifetime values than is possible with thin, surface-limited samples such as silicon wafers.

Abstract: Methods (600) and systems (100) for inspecting an indirect bandgap semiconductor structure (140) are described. A light source (110) generates light (612) suitable for inducing photoluminescence in the indirect bandgap semiconductor structure (140). A short-pass filter unit (114) reduces long-wavelength light of the generated light above a specified emission peak. A collimator (112) collimates (616) the light. A large area of the indirect bandgap semiconductor structure (140) is substantially uniformly and simultaneously illuminated (618) with the collimated, short-pass filtered light. An image capture device (130) captures (620) images of photoluminescence simultaneously induced by the substantially uniform, simultaneous illumination incident across the large area for the indirect bandgap semiconductor structure.

Abstract: A method (1) is disclosed whereby luminescence images are captured (2) from as-cut or partially processed bandgap materials such as multicrystalline silicon wafers. These images are then processed (3) to provide information about defects such as dislocations within the bandgap material. The resultant information is then utilised (4) to predict various key parameters of a solar cell manufactured from the bandgap material, such as open circuit voltage and short circuit current. The information may also be utilised to apply a classification to the bandgap material. The methods can also be used to adjust or assess the effect of additional processing steps, such as annealing, intended to reduce the density of defects in the bandgap materials.

Abstract: Methods are presented for separating the effects of background doping density and effective minority carrier lifetime on photoluminescence (PL) generated from semiconductor materials. In one embodiment the background doping density is measured by another technique, enabling PL measurements to be analyzed in terms of effective minority carrier lifetime. In another embodiment the effective lifetime is measured by another technique, enabling PL measurements to be analyzed in terms of background doping density. In another embodiment, the effect of background doping density is removed by calculating intensity ratios of two PL measurements obtained in different spectral regions, or generated by different excitation wavelengths. The methods are particularly useful for bulk samples such as bricks or ingots of silicon, where information can be obtained over a much wider range of bulk lifetime values than is possible with thin, surface-limited samples such as silicon wafers.

Abstract: A method is disclosed whereby luminescence images are captured from as-cut or partially processed bandgap materials such as multicrystalline silicon wafers. These images are then processed to provide information is then utilized to predict various key parameters of a solar cell manufactured from the bandgap material, such as open circuit voltage and short circuit current. The information may also be utilized to apply a classification to the bandgap material. The methods can also be used to adjust or assess the effect of additional processing steps, such as annealing, intended to reduce the density of defects in the bandgap materials.

Abstract: Methods and systems are presented for acquiring photoluminescence images (2) of silicon solar cells and wafers (4) as they progress along a manufacturing line (36). In preferred embodiments the images are acquired while maintaining motion of the samples. In certain embodiments photoluminescence is generated with short pulse, high intensity excitation, (8) for instance by a flash lamp (50) while in other embodiments images are acquired in line scanning fashion. The photoluminescence images can be analysed to obtain information on average or spatially resolved values of one or more sample properties such as minority carrier diffusion length, minority carrier lifetime, dislocation defects, impurities and shunts, or information on the incidence or growth of cracks in a sample.