Photovoltaic distribution on an amorphous-silicon solar cell in near-band-edge excitation observed by conductive-probe atomic force microscopy combined with a fine-wavelength-tunable light source.

We describe the development of a conductive-probe atomic force microscopy method combined with a fine-wavelength-tunable light source and use it to observe the photovoltaic distribution on a cross-sectional surface of an amorphous-silicon solar cell in near-band-edge excitation. The light source's wavelength resolution is dλ = 1 nm, and its intensity is 1 µW/cm2 (10 mW/m2); this excitation condition is sufficiently fine and weak to investigate electrical properties in the near-band-edge wavelength range. The photovoltage is observed in the indium tin oxide (ITO) region, and the maximum photovoltage increases when we increase the excitation energy of the illumination light. However, the photovoltaic distribution parallel to the ITO layer becomes relatively localized as the excitation energy increases. This localized photovoltaic distribution suggests that the conductivity of the electric current path within the ITO layer should be inhomogeneous.

Adhesive Materials Utilizing a Thymine-Adenine Interaction and Thymine Photodimerization.

A cross-linking reagent having two adenine units was mixed with polymers bearing thymine units to form adhesive materials utilizing both intermolecular hydrogen bonding and in situ formation of covalent bonds. In the case of 58 mol % of adenine units relative to thymine units, formation of intermolecular hydrogen bonds because of a thymine-adenine interaction was observed at room temperature using FT-IR. The peel strength became weak with heating above 60 °C, indicating breakup of intermolecular bonds between thymine and adenine units. On the other hand, UV-vis spectral measurements showed that heating at 80 °C with 254 nm light irradiation facilitated the photodimerization reaction between thymine units even in the presence of adenine cross-linking reagents. This result was consistent with a large value for the peel strength (6.5 N/10 mm) after the dual treatment, heating at 80 °C with 400 mJ/cm2 of UV irradiation.

Development and application of an internet electron microscopy system for the outreach program in Japan.

The development of a remotely operated scanning electron microscopy (SEM) system and its use by high school students and the public as an outreach program are reported. The SEM and the server are located in the National Institute for Materials Science, Tsukuba, Japan, with client computers installed at a science museum and high schools. Using a secure virtual private network system and scheduling/management groupware, observation of SEM images and energy dispersive X-ray analysis are widely and frequently performed throughout Japan.

Grazing exit electron probe microanalysis of submicrometer inclusions in metallic materials.

Grazing exit electron probe microanalysis (GE-EPMA) is a new method of EPMA in which characteristic X-rays emitted from only near-surface regions of a specimen are detected at extremely low exit angles near 0 degrees (the grazing exit condition). This technique requires the analytical objects exist on a flat surface. Therefore, the GE-EPMA analysis has been used only for the analysis of particles or a thin film on a flat substrate so that there were only few applications for practical analysis. As a new application, we have carried out GE-EPMA analysis of approximately 0.2-microm inclusions on stainless steel, which appeared to be a projection on the specimen surface with chemical etching. The GE-EPMA quantitative results were in excellent agreement with those of inclusions that were extracted from the stainless steel and analyzed by EPMA with conventional exit condition (30 degrees). This method could be, therefore, applied to the analysis of the submicrometer inclusion in a wide variety of metallic materials if the inclusion appears to be a projection with chemical etching treatment.