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The thickness of the CdS:O window layer plays an important role in CdTe-based thin-film solar cell performance. Normally with thinner CdS:O layer, the cells’ short wavelength response can be enhanced to achieve higher short-circuit current density (Jsc), while the open-circuit voltage (Voc) and fill factor (FF) would degrade. Previous research finds that reducing the CdS:O layer thickness to less than 40 nm would decrease the cells’ efficiency (Eff.). In this work, 18% efficiency CdTe thin-film solar cell with only 30 nm CdS:O window layer is demonstrated. A post annealing process is developed to fabricate high efficiency cells with ultrathin CdS:O layers. Our results indicate that the high defect density in CdTe absorber, low built-in potential (Vbi) and high back contact barrier (Φb) are partially responsible for the reduced Voc and FF of cells with ultrathin CdS:O layers. The post annealing process can increase the carrier concentration (NCV) and Vbi, and decrease the Φb, in which way improves Voc and FF for higher cell efficiency.

The Sudbury Neutrino Observatory will use an array of 9500 Hamamatsu R1480 8-in. photomultiplier tubes and their associated concentrators to detect Cherenkov light. This paper describes an experimental investigation of the photomultiplier tubes and their concentrators, together with work done to model the angular and wavelength response. Good agreement is achieved.

The effect of surface recombination velocity on the short wavelength response of the tandem junction solar cell is investigated theoretically. The analysis predicts approximately the same dependence of the short-circuit current on surface recombination velocity as for a conventional p-n junction solar cell. It is concluded that the experimentally observed improvement in the blue response of the tandem junction solar cell is probably due to a small surface recombination velocity as a result of the absence of front-surface metallization.

Directional growth was induced in the conchocelis phase of Porphyra umbilicalis (L.) J. Ag. by prolonged unilateral light. The filaments of the conchocelis exhibited negative phototropism when irradiated with monochromatic light of wavelengths between 400–500 nm. Fragmented filaments were used for the experiments on phototropism; after a growing period of 4 wk, these filaments showed a phototropic reaction to continuous unilateral light within 1 day. The photoropic response increased in proportion to the logarithm of the photon flux density of the monochromatic light. The wavelength response curve showed similarities with phototropic action spectra found in the literature except that there was an additional peak near 400 nm. Phototropism was also demonstrated in ten other species of red algae, the rhizoids of which showed a negative response. The filaments of some species grew towards light.

A two-dimensional head model with an infinitely permeable core wrapped with an infinitesimally thin winding provides the best possible resolution. The readback wavelength response for a model when an ideal winding covers the magnetic core up to the core tips is the autoconvolution of the response of a head with the same core and the winding at infinity. Usage of this relationship facilities the evaluations of theoretical limits of characteristics of real heads.