(a) A cross-sectional SEM image of the sample prepared at 270 Pa. TEM images of the sample prepared at (b) 270 and (c) 1100 Pa.
(a) bond density as a function of exposure time to the atmosphere and (b) the ratio of absorption intensity of decomposed groups to the total absorption intensity at around . The circles, squares, and triangles represent nanocrystal films prepared at 270, 530, and 1100 Pa, respectively. The broken lines are fitting curves.
Changes in the IR absorption spectra at around by natural oxidation. Arrows in the figure show the estimated vibrational frequency of groups. The inset shows the spectrum measured within 10 min after the exposure to the atmosphere.
PL emission spectra of the nanocrystal film prepared in hydrogen gas at 530 Pa measured at various exposure times to the atmosphere.
PL peak shift as a function of time within 5 min after exposure to the atmosphere for the nanocrystal film prepared at 1100 Pa. The PL peak wavelength of the as-deposited nanocrystal film measured without breaking vacuum was 800 nm. This peak shifted to 660 nm at 5 min. The 660 nm peak shifted back to a longer wavelength, 730 nm, when we evacuated again to about .
PL peak wavelength as a function of bond density. The circles, squares, and triangles represent nanocrystal films prepared at 270, 530, and 1100 Pa, respectively.
A simplified schematic view of structure of deposits.
The exothermic energy as a function of number of units. The solid circle, triangle, and cross correspond to the (111) surface, (100) surface, and edge. The solid line indicates estimated exothermic energy to generate bonds in the molecule.
The best fitted values of and . These values are obtained by using Eq. (2) and fitted curves are shown in Fig. 2(a).
Article metrics loading...
Full text loading...