The optical properties of thin films of Co、Ti、Si and crystals of LSO and YVO4

• Main Authors: TSAO,YIU-HAO, 曹祐豪
• Other Authors: WU,KUNG-TUNG
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/32736841638118662159

碩士 === 輔仁大學 === 物理學系 === 93 === Abstract The paper attempts to explain the use of electron beam evaporation in making multilayers of three different thicknesses.We discussed the influences of different materials, different number of layers and surface roughness to transmission of light. Also, the transmission spectra of LSO crystals and YVO4 crystals of different thicknesses were measured for the discussion of the relation among transmission, thickness of crystal and the wavelength of light. First, three different thicknesses, 80Å, 100Å and 120 Å, of thin films were made with electron beam evaporation, and each thickness consists of single layer of titanium, cobalt, silicon, and multilayer of cobalt- titanium, titanium- silicon and cobalt- silicon. Using the Cary 5E spectrophotometer, the transmission spectra of each specimen were measured and the surfaces of specimens were observed by using atomic force microscope. The influence of thickness, number of layers and material to the transmission, and surface roughness of thin films were analyzed, as well as the relation between the number of layers and surface roughness. It was discovered that there are two similar characteristics in the transmission spectra of titanium, cobalt and silicon, i.e. the cutoff wavelengths are all approximately at 250nm and there is a clear drop at 2750nm. For the same material, the transmission decreases as the thickness of material increases. For different material of the same thickness, the transmission of thin films of silicon is higher than that of titanium and cobalt. For the multilayer consisting of two different materials of the same thickness, the transmission falls between that of these two materials, and as the number of layers increases, the transmission tends to drop. Cutting the LSO crystal of 1mm, 2mm and 3mm and the YVO4 crystal of 1.5mm, 2.5mm and 3.5mm respectively, their transmission spectra were measured. As a result, it was discovered that in the range of ultraviolet, i.e. when the wavelength smaller than 400nm, the transmission of the LSO crystal of three different thicknesses oscillated, and the transmission of the crystal of 1mm thick is higher than that of 2mm and 3mm,i.e. the transmission increases as the thickness of material decreases. The transmission of the annealed YVO4 crystal was higher than that was not annealed in the same thickness.