2007, Vol.17, No.2

Journal of the Korean Crystal Growth and Crystal Technology 2023 KCI Impact Factor : 0.19

pISSN : 1225-1429 / eISSN : 2234-5078
https://journal.kci.go.kr/jkcgct

F-doped SiOC : H thin films with low refractive index were deposited on Si wafer and glass substrate by plasma enhanced chemical vapor deposition (PECVD) as a function of rf powers, substrate temperatures, gas rates and their composition flow ratios (SiH4, CF4 and N2O). The refractive index of the F-doped SiOC : H film continuously decreased with increasing deposition temperature and rf power. As N2O gas flow rate decreased, the refractive index of the deposited films decreased down to 1.3778, reaching a minimum value at rf power of 180W and 100 o C without N2O gas. The fluorine content of F-doped SiOC : H film increased from 1.9 at% to 2.4 at% as the rf power was increased from 60W to 180W, which results in the decrease of refractive index.

We have installed an ultra high vacuum (UHV) molecular beam epitaxy (MBE) system and investigated into the characteristics of MBE-grown ZnSe/GaAs [001] using scanning electron microscopy (SEM), atomic force microscopy (AFM), we confirmed that layer's surface was dense and uniform of molecular layer. We used x-ray diffractometer (XRD) and confirmed two peaks correspond to GaAs [001] substrate and ZnSe epilayer, respectively. We observed photoluminescence (PL) peak approximately at 437 nm and measured PL mapping of 2 inch ZnSe epilayer.

Willemite green phosphor powders have been prepared by the metallo-organic decomposition (MOD) method, and the photoluminescence and phase formation were studied as a function of both the firing temperature (800~1100oC) and the concentration of Mn activator (4~12 mol%). Under 254 nm excitation source, the emission intensity of the phosphors increased with increasing the firing temperature from 800 to 1000oC. From the XRD analysis, the powders heattreated above 1000oC showed willemite crystal structure. The maximum emission intensity was obtained for the phosphors heat-treated at 1000oC with 8 mol% of Mn content. The concentration quenching was occurred when the Mn concentration exceeded 10 mol%. The phosphor particles showed spherical shapes with the average size of 0.4~0.5 μm by the SEM morphology.