Protein glycosylation is one of the most common posttranslational modifications in eukaryotes and affects various aspects of protein structure and function. To facilitate studies of protein glycosylation, we paired glycosylation site-specific stable isotope tagging of lectin affinity-captured N-linked glycopeptides with mass spectrometry and determined 1,465 N-glycosylated sites on 829 proteins expressed in Caenorhabditis elegans. The analysis shows the diversity of protein glycosylation in eukaryotes in terms of glycosylation sites and oligosaccharide structures attached to polypeptide chains and suggests the substrate specificity of oligosaccharyltransferase, a single multienzyme complex in C. elegans that incorporates an oligosaccharide moiety en bloc to newly synthesized polypeptides. In addition, topological analysis of 257 N-glycosylated proteins containing a putative single transmembrane segment that were identified based on the relative positions of glycosylation sites and transmembrane segments suggests that an atypical non-cotranslational mechanism translocates large N-terminal segments from the cytosol to the endoplasmic reticulum lumen in the absence of signal sequence function.

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Semiconducting barium disilicide (BaSi2) is a promising material for solar cell and thermoelectric applications; hence, high-mobility films are of great importance. In this study, we achieved substantially high electron mobilities exceeding 103 cm2 V−1 s−1 at 300 K in randomly oriented polycrystalline BaSi2 films formed on Si3N4 insulating films at 600 °C through radio-frequency sputtering. The BaSi2 films consisted of small grains (<0.5 µm in diameter), and the electron concentration was in the order of 1015–1016 cm−3. Kelvin probe force microscopy revealed that the root-mean-square surface potential values were lower than 31 mV, indicating that the grain boundaries did not hinder electron transport. The potential barrier height across positively charged cracks on the surface of the BaSi2 films, wherein oxidation proceeded, was as small as 30–40 mV. These results indicate that polycrystalline BaSi2 films/insulating films with high electron mobilities are useful for various electronic device applications.

We formed randomly oriented polycrystalline BaSi2 films on TiN(metal)/SiO2 substrates at 600 °C by co-sputtering BaSi2 and Ba targets. Ba-to-Si atomic ratios reaching the substrate (N Ba/N Si = 0.28–0.76) was controlled by a radio-frequency power set on the Ba target (P Ba = 0–80 W), while that on the BaSi2 target was fixed at 70 W. The highest photoresponsivity was obtained when P Ba was set to as a small value as possible to the extent without causing precipitated Si to occur. This is the same simple way of finding the conditions to achieve high photoresponsivity as that for BaSi2 epitaxial films.

Semiconducting BaSi2 has attractive features for thin-film solar cell applications. In this study, we investigated the potential of NiO as a hole transport layer (HTL) in NiO/BaSi2 heterojunction solar cells both by simulation and by experiment. To find deposition conditions to form NiO layers, a NiO target was sputtered on glass substrates under various O2-to-Ar gas flow ratios. The hole concentration of the NiO films was controlled in the range 1017 – 1021 cm-3 mainly by the substrate temperature during deposition. After that, NiO/BaSi2 heterojunction solar cells were designed using a one-dimensional simulation software (AFORS-HET v2.5). The conversion efficiency exceeded 17% for 400-nm-thick n-BaSi2 absorption layers. We actually formed NiO/BaSi2 heterojunction solar cells on glass substrates by radio-frequency sputtering, and demonstrated that the carriers photogenerated in the BaSi2 films contributed to the internal quantum efficiency spectrum at wavelengths shorter than approximately 900 nm, corresponding to the band gap of BaSi2.