RESUMO
We present a compact dot marker using a CW laser on a microcrystalline silicon (Si) thin film. A laser annealing shows a continuous crystallization transformation from nano to a large domain (> 200 nm) of Si nanocrystals. This microscale patterning is quite useful since we can manipulate a two-dimentional (2-D) process of Si structural forms for better and efficient thin-film transistor (TFT) devices as well as for photovoltaic application with uniform electron mobility. A Raman scattering microscope is adopted to draw a 2-D mapping of crystal Si film with the intensity of optical-phonon mode at 520 cm(-1). At a 300-nm spatial resolution, the position resolved the Raman scattering spectra measurements carried out to observe distribution of various Si species (e.g., large crystalline, polycrystalline and amorphous phase). The population of polycrystalline (poly-Si) species in the thin film can be analyzed with the frequency shift (delta omega) from the optical-phonon line since poly-Si distribution varies widely with conditions, such as an irradiated-laser power. Solid-phase crystallization with CW laser irradiation improves conductivity of poly-Si with micropatterning to develop the potential of the device application.
RESUMO
Crystals of 2,4,6-triamino-1,3,5-triazin-1-ium levulinate (4-oxopentanoate) monohydrate, C(3)H(7)N(6)(+).C(5)H(7)O(3)(-).H(2)O, are formed via self-assembled hydrogen bonding by cocrystallization of melamine and levulinic acid. Two N-H.N hydrogen bonds and four N-H.O hydrogen bonds connect two melaminium entities such that each of two pairs of N-H.O bonds bridges two H atoms belonging to the amine groups of two different melaminium cations via the carbonyl O atom of one levulinate molecule.
