Data on dopant characteristics and band alignment of CdTe cells with and without a ZnO highly-resistive-transparent buffer layer.

Photovoltaic enhancement of cadmium telluride (CdTe) thin film solar cells using a 50 nm thick, atomic-layer-deposited zinc oxide (ZnO) buffer film was reported in "Enhancement of the photocurrent and efficiency of CdTe solar cells suppressing the front contact reflection using a highly-resistive ZnO buffer layer" (Kartopu et al., 2019) [1]. Data presented here are the dopant profiles of two solar cells prepared side-by-side, one with and one without the ZnO highly resistive transparent (HRT) buffer, which displayed an open-circuit potential (Voc) difference of 25 mV (in favor of the no-buffer device), as well as their simulated device data. The concentration of absorber dopant atoms (arsenic) was measured using the secondary ion mass spectroscopy (SIMS) method, while the density of active dopants was calculated from the capacitance-voltage (CV) measurements. The solar cell simulation data was obtained using the SCAPS software, a one-dimensional solar cell simulation programme. The presented data indicates a small loss (around 20 mV) of Voc for the HRT buffered cells.

Experimental confirmation of the predicted shallow donor hydrogen state in zinc oxide.

We confirm the recent prediction that interstitial protium may act as a shallow donor in zinc oxide, by direct spectroscopic observation of its muonium counterpart. On implantation into ZnO, positive muons--chemically analogous to protons in this context--form paramagnetic centers below about 40 K. The muon-electron contact hyperfine interaction, as well as the temperature and activation energy for ionization, imply a shallow level. Similar results for the cadmium chalcogenides suggest that such shallow donor states are generic to the II-VI compounds. The donor level depths should serve as a guide for the electrical activity of interstitial hydrogen.

First Report of Colletotrichum acutatum on Kalmia.

Colletotrichum acutatum J. H. Simmonds was isolated from diseased leaves of ornamental Kalmia latifolia L. (mountain laurel) cvs. Carousel and Peppermint on plants imported from the United States to Edinburgh, Scotland, in December 1999. Symptoms included sunken, desiccated, darkened necrotic areas, primarily at the leaf tip. Necrotic areas advanced toward the leaf base and were bordered by purple/red pigmentation. Isolations were made from salmon colored conidiomata that developed on abaxial leaf surfaces following incubation in a humidity box at 25°C for 7 to 10 days. White aerial mycelia, becoming gray to grayish beige, and producing salmon to orange colored conidial masses, formed on potato dextrose agar after 10 to 14 days. Conidia were hyaline, aseptate, fusiform to slightly irregular, and measured 13.4 to 13.8 × 4.3 to 4.9 µm. Both morphological and conidial characteristics were consistent with the description of C. acutatum (2). The identity of isolates was further verified by positive plate-trapped antigen ELISA of conidial preparations using a species-specific monoclonal antibody (1). Pathogenicity was assessed by inoculating the adaxial surface of healthy leaves of both cultivars of the imported plants with colonized agar disks and a range of spore suspensions (30, 300, and 3,000 spores delivered in 30 µl volumes) from test fungal isolates and a confirmed laboratory strain (three replicates per treatment). To ensure inoculum uptake, two 5 mm2 areas of cuticle on either side of the mid-rib of each leaf were lightly scratched with a sterile hyperdermic needle prior to inoculation. Inoculated leaves were incubated in a humidity box at 25°C for up to 3 weeks. Symptom development was progressive but relatively slow on both cultivars. The relatively slow development on artificially infected leaf material may be partly attributable to residual fungicide treatment as prescribed by the Scottish Plant Health Service at the time of planting out. Symptoms produced on fruits (apple, banana, and strawberry), inoculated with both test and laboratory strains of the fungus, were identical. Symptoms did not occur on control leaves or fruits inoculated with sterile distilled water or uninoculated agar disks. Koch's postulates were confirmed by consistently reisolating isolates with morphological and immunological characteristics identical to the fungal isolate used to initially inoculate test material. Over the same period, additional symptoms, identical to those originally described at the time of interception, continued to develop on leaf tips of both Kalmia cultivars. Additional isolations from this material were characterized as C. acutatum. Identification of representative isolates was confirmed by CABI Bioscience, Egham, UK, where a reference culture (accession number IMI 384569) has been deposited. As advanced symptoms were observed immediately on arrival of this consignment in the UK, original infection is thought to have occurred prior to importation. This is the first report of C. acutatum infecting K. latifolia. References: (1) I. Barker et al. 1994. Pages 179-182 in: Assays for Plant Pathogenic Fungi: Identification, Detection and Quantification. A. Schots, F. M. Dewey, and R. Oliver, eds. CABI International, Wallingford, UK. (2) B. J. Dyko and J. E. M. Mordue. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 630, 1979.