A. C. Ribes

Reflected-light, photoluminescence and OBIC imaging of solar cells using a confocal scanning laser MACROscope/microscope

Abstract This paper describes a confocal scanning beam MACROscope/Microscope which can image specimens up to 7 × 7 cm in size using reflected light, photoluminescence and optical beam induced current. The MACROscope provides a 10 μm spot size at various wavelengths and generates 512 × 512 pixel images in less than 5 s. When used in combination with a conventional confocal scanning laser microscope sub-micron spot sizes become possible providing resolutions as high as 0.25 μm laterally and 0.5 μm axially in reflected light. The main function of this imaging system is to spatially resolve any defects within solar cells and similar devices. Several reflected-light, photoluminescence and OBIC images of CdS CuInSe 2 and CdZnS CuInSe 2 thin film solar cells are presented.

Photoluminescence imaging of porous silicon using a confocal scanning laser macroscope/microscope

This letter describes a confocal scanning beam macroscope/microscope that can image specimens up to 7 cm in diameter using both photoluminescence and reflected light. The macroscope generates digital images (512×512 pixels) with a maximum 5 μm lateral resolution and 200 μm axial resolution in under 5 s, and in combination with a conventional confocal scanning laser microscope can provide quality control at a macroscopic/microscopic level for porous silicon specimens, wafers, detectors, and similar devices. This combination of instruments can also be used as a method for evaluating preparation parameters involved in the manufacture of porous silicon. Various confocal and nonconfocal photoluminescence and reflected‐light images of porous silicon are shown using both a macroscope and a conventional confocal scanning laser microscope. A 3D profile of a porous silicon structure reconstructed from confocal slices is also shown.

A new confocal scanning beam laser MACROscope using a telecentric, f‐theta laser scan lens

A new confocal scanning beam system (MACROscope) that images very large‐area specimens is described. The MACROscope uses a telecentric, f‐theta laser scan lens as an objective lens to image specimens as large as 7·5 cm × 7·5 cm in 5 s. The lateral resolution of the MACROscope is 5 μm and the axial resolution is 200 μm. When combined with a confocal microscope, a new hybrid imaging system is produced that uses the advantages of small‐area, high‐speed, high‐resolution microscopy (0·2 μm lateral and 0·4 μm axial resolution) with the large‐area, high‐speed, good‐resolution imaging of the MACROscope. The advantages of the microscope/MACROscope are illustrated in applications which include reflected‐light confocal images of biological specimens, DNA sequencing gels, latent fingerprints and photoluminescence imaging of porous silicon.

A scanning beam time-resolved imaging system for fingerprint detection.

A highly sensitive confocal scanning-beam system for time-resolved imaging of fingerprints is described. Time-resolved imaging is a relatively new forensic procedure for the detection and imaging of latent fingerprints on fluorescent substrates such as paper, cardboard, and fluorescent paint. Ordinary fluorescent imaging of latent fingerprints on these surfaces results in poor contrast. Instead, the specimens are treated with a phosphorescent dye that preferentially adheres to the fingerprint which allows time-resolved discrimination between the fingerprint phosphorescence and the background fluorescence. Time resolved images are obtained by synchronizing the digital sampling of the specimen luminescence with the on-off cycle of the chopped illumination beam. The merit of this technique is illustrated with high contrast images of fingerprints obtained from the fluorescent painted surface of a Coke can.

Confocal imaging of porous silicon with a scanning laser macroscope/microscope

Abstract High resolution, large area photoluminescence mapping with scanning stage microscopes has proven to be a useful, but slow, quality control technique for compound semiconductor wafers. This paper describes a confocal scanning beam MACROscope-Microscope which can image specimens up to 7.5×7.5 cm in size, in less than 10s, using reflected light, photoluminescence, and optical beam induced current. MACROscope mode provides 5 μm lateral resolution and 300 μm axial resolution. Microscope mode provides 0.25 μm lateral and 0.5 μm axial resolution, with a minimum field of view of 25×25 μm. This instrument can be used to evaluate preparation parameters involved in the manufacture of porous silicon as well as to provide quality control at a macroscopic and microscopic level for the fabrication of porous silicon specimens, wafers, detectors, and similar devices. A brief introduction to confocal microscopy and porous silicon is given. Several confocal and non-confocal photoluminescence and reflected-light images of a porous silicon wafer are shown at macroscopic and microscopic levels. A 3D profile of porous silicon structures reconstructed from confocal slices is also shown.

Confocal scanning beam laser microscope/macroscope: applications in fluorescence

A new confocal scanning beam laser microscope/macroscope is described that combines the rapid scan of a scanning beam laser microscope with the large specimen capability of a scanning stage microscope. This instrument combines an infinity-corrected confocal scanning laser microscope with a scanning laser macroscope that uses a telecentric f*(Theta) laser scan lens to produce a confocal imaging system with a resolution of 0.25 microns at a field of view of 25 microns and 5 microns at a field of view of 75,000 microns. The frame rate is 5 seconds per frame for a 512 by 512 pixel image, and 25 seconds for a 2048 by 2048 pixel image. Applications in fluorescence are discussed that focus on two important advantages of the instrument over a confocal scanning laser microscope: an extremely wide range of magnification, and the ability to image very large specimens. Examples are presented of fluorescence and reflected-light images of high quality printing, fluorescence images of latent fingerprints, packaging foam, and confocal autofluorescence images of a cricket.

Confocal scanning beam laser microscope/macroscope: applications requiring large data sets

A new confocal scanning beam laser microscope/macroscope is described that combines the rapid scan of a scanning beam laser microscope with the large specimen capability of a scanning stage microscope. This instrument combines an infinity-corrected confocal scanning laser microscope with a scanning laser macroscope that uses a telecentric f*(theta) laser scan lens to produce a confocal imaging system with a resolution of 0.25 microns at a field of view of 50 microns to 5 microns at a field of view of 75,000 microns. The frame rate is 3 seconds per frame for a 512 X 512 pixel image, and 45 seconds for a 2048 X 2048 pixel image. Changes made in the instrument to increase the image capture from 512 X 512 pixels to 2048 X 2048 pixels are described. Applications discussed focus on three important advantages of the instrument over a confocal scanning laser microscope: an extremely wide range of magnification, the ability to record very large data sets, and the ability to image very large specimens. Examples are presented from imaging of fibers in paper, latent fingerprint detection, and reflected-light and photoluminescence imaging of porous silicon.

A New Confocal Scanning Laser MACROscope/Microscope Applied to the Characterization of Solar Cells

Scanning stage microscopes have traditionally been used to provide high resolution, large area photocurrent mapping of solar cells and detectors. This imaging method, while very useful in the characterization and quality control of solar cells, is unfortunately slow (image acquisition takes several minutes). This paper describes a confocal scanning beam MACROscope-Microscope which can image specimens from 25 x 25 {micro}m up to 7.5 x 7.5 cm in size, a zoom factor of 3,000, using reflected light, photoluminescence, and optical beam induced current in less than 10s. Resolutions range from 0.25 to 10 {micro}m laterally and 0.5 to 300 {micro}m axially depending upon whether microscope of MACROscope mode is used. This instrument can therefore be used to characterize and provide quick and efficient quality control for solar cells and detectors at a microscopic and macroscopic level. A brief description of the MACROscope-Microscope is given. The MACROscope-Microscope`s many abilities are highlighted by showing various reflected-light, photoluminescence and optical beam induced current images from CdZnS/CuInSe{sub 2} thin film solar cells and porous silicon devices.