, Akishima, Tokyo, Japan) and a 2010 F microscope operating at 120 and 200 kV, respectively. The latter is equipped with an Oxford Instruments’ EDX detector. For these measurements, the NWs were scraped from the substrate and dispersed on a lacey carbon-coated copper grid. Results and discussion Just after growing the NWs and before performing any irradiation, EDX-SEM analysis (not shown here, see Additional file 1) confirmed that the ZnO film composition was very close to the stoichiometric one (O 50.50%, Zn 49.5%). In order to determine if the irradiation could affect the ZnO NW morphology, HR-SEM analyses were performed. Figure 1a,b

shows the SEM images from as-grown JNK-IN-8 datasheet unirradiated NWs, with AC220 cell line the presence of a quite homogeneous ZnO NW cover layer on top of the ZnO film. Noticeable morphology changes can be observed on the surfaces of the films after irradiation (Figure 1c,d) where the images evidence a reduction of the thinner ZnO NW population, and only relatively thicker NWs can be observed. This is still more evident for the highest fluence (Figure 1e,f). Thus, it can be concluded that, at least for the fluences used in this work, the thinner NWs (diameter (d) < 200 nm) do not survive the irradiation process, especially at higher fluences (1017 cm−2). In

addition, the remaining NWs seem increasingly thicker https://www.selleckchem.com/products/bix-01294.html when the irradiation fluence increases. Figure 1 High-resolution SEM images. Showing the morphology of unirradiated ZnO NWs (a, b) and irradiated NWs with fluences of 1.5 × 1016 cm−2 (c, d) and 1017 cm−2 (e, f). Note the disappearance of the thinner NWs as the Resveratrol irradiation fluence increases. Before any structural or optical characterization, the irradiated areas were observed by the naked eye when illuminating under UV light (at 365 and 254 nm). A clear color change was detected

with respect to the unirradiated areas; the irradiated ones appear black (not shown here, see Additional file 2). This was the first evidence of an important change in the optical emission properties of the samples, which motivated a detailed optical characterization of the irradiated structures. For a more in-depth study, μPL measurements were performed at RT on both the unirradiated and irradiated areas (Figure 2). The two typical emissions of ZnO were always observed, a strong NBE UV emission (approximately 3.26 eV) due to the direct recombination of photogenerated charge carriers or excitons [33] and a broad visible emission band (approximately 2.25 eV) involving deep levels. It is proposed that the visible emission (DLE) in ZnO originates from the contribution of at least three subbands, i.e., the so-called green band (green luminescence (GL), at approximately 2.4 eV (approximately 515 nm)), the yellow band (yellow luminescence (YL), at approximately 2.