SEM images of BiNPs grown at 200°C and 0 12 W/cm2 for different d

SEM images of BiNPs grown at 200°C and 0.12 W/cm2 for different deposition durations learn more (10 to 60 s) are shown in Figure 2a,b,c,d,e,f. Unlike the thin film-like samples grown at low temperatures, all samples grown at 200°C showed distinct particle-like BiNPs. By depositing samples at this temperature with different durations, we were able to control the size of the BiNPs. Furthermore, samples deposited for shorter durations (10 to 40 s) showed spherical-shape BiNPs, but samples deposited for longer durations (50 and 60 s) showed crystal-like BiNPs. This crystallization behavior can be identified by the XRD pattern (figure not shown here). The ratio of the

diffraction peak of the preferred orientation to the other minor peaks becomes stronger as the deposition duration increases. Figure GSI-IX nmr 2 SEM images of BiNPs deposited on glass substrates at 200°C and 0.12 W/cm 2 for different deposition durations. (a) 10 s, (b) 20 s, (c) 30 s, (d) 40 s, (e) 50 s, and (f) 60 s, which correspond to sample Bi-201 to Bi-206 in Table 1. Particle size distribution of samples Bi-201

to Bi-206 can be obtained by measuring the diameters from the SEM images. We use a simple computer program to examine every SEM image file pixel-by-pixel, and the shapes of the BiNPs are identified by their color differences (the color on the substrate is darker than on the nanoparticles). By summing up the pixels, the area of each nanoparticle can be determined, and thus its diameter. In this way, we can calculate the mean diameter of any form within a fixed area of 3.5 μm2. The results are shown in Figure 3, and some of the important statistical values are listed in Table 3. Note that the average diameter of the sample is , the standard deviation of each sample is , and the peak of lognormal fitting [27] is , which corresponds to the mode. There are apparently two lognormal fitting peaks for 50- and 60-s deposited samples, which means that there exist two particle sizes. During the sputtering process, two BiNPs merged to form

a larger particle, so extra space emerged as new BiNPs begin to grow. Minimum area for BiNP Urease nucleation can therefore be estimated to be 2.5 × 102 nm2. As a consequence, all of the abovementioned statistical parameters ( , , and ) increase with the deposition time, but the time dependence of the BiNP density shows a minimum density at 40 s. Figure 3 Particle size distribution statistics and lognormal fitting. (a-d) Samples Bi-201 to Bi-204, and (e, f) samples Bi-205 and Bi-206. The analysis is carried out from SEM images within a fixed area of 3.5 μm2. Table 3 Particle size statistics and estimated bandgap of samples Bi-201 to Bi-206 Number (nm) (nm) (nm) E g (eV) Bi-201 12.9 13.0 13.2 2.63 Bi-202 17.5 18.5 18.9 2.50 Bi-203 21 20.7 21.7 0.85 Bi-204 28.7 28.9 29.9 0.91 Bi-205 14.5 and 45.1 38.3 42.3 1.39 Bi-206 15.3 and 52.6 41.1 45.9 0.45 Bi-101       0.

Comments are closed.