Abstract
考慮電子在異常肌膚效應和在薄膜邊界的散射下,入射光能量從0.0到4.0eV的光學穿透率,反射率和吸收率對金膜而言,其最大穿透率發生在0.5eV,此乃遠低於其電漿子振盪頻率,藉由金屬和介電質的多層膜所設計出來的窄頻寬光學濾波,器可達頻寬排斥率(band rejection ratio)48.5.藉由形體效應的理論,推導得出電磁場強度在金屬薄膜內的分佈情形,在異常肌膚效應下,幾乎為平面波,而且高階電磁場項只有在邊界參數p和q值非常小時,才有貢獻,另外,分析電磁場分佈因傳導電子在金屬薄膜表面附近的散射行為所造成的影響,再者,因電子的鬆弛時間受入射光頻率和溫度的效應,亦即鬆弛時間的倒數和溫度的平方成正比且或和頻率的平方成正比將可造成高階電磁場項的誤差達5.5%,是故金屬內能滿足平面波波包的估計模型.利用橢圓偏光角度研究形體效應的理論計算和實驗測量,改變銀薄膜厚度從12.5到200.0nm的橢圓偏光角度psi和 delta來印證金屬薄膜的古典形體效應,其在銀薄膜厚度為 12.5nm時的誤差分別41.7%和-21.5%,並藉由原子力顯微鏡來觀察銀薄膜的表面粗糙程度約為6.0nm.得以印證理論計算和實驗測量和薄膜的表面粗糙(roufhness)和去極化現象(depolarization)的影響程度.因此其並不會在橢圓偏光角度研究光學係數,由於形體效應之故,造成薄膜的光學特性之無法決定.The optical wave transmittance, reflectance, and absorptance ofthin metallic films with photon energies from 0.0 to 4.0eV arecalculated by considering the anomalous skin effect andelectron scattering at the film boundaries. A narrow-bandrejection filter can be constructed from metal- dielectricsmultilayers with a rejection ratio of 48.5 for a 10-layerstructure. The nearly plane wave solution exp(-uWz), theelectric field may contain higher-order terms that contributeconsiderably to the total field when the specularity parametersp and q are small. The profile distribution of the electricfield oscillates considerably near the surface as boundaryscattering of the conduction electrons becomes prominent.Further, the frequency and temperature dependence the sizeeffect on the profile distribution of electromagnetic fieldsinside thin metallic films within the anomalous skin effectregion is theoret- ically studied. The errors of using theplane wave solution turns out to be as large as 5.5% comparedto the total field including the higher-order terms for silverfilms with a thickness of 30.0nm. Both theoretical andexperimental works are studied for the ellipsometry of thinmetallic films with thickness varying from 12.5nm to 200.0nm.The ellip- sometry angles psi and delta deviated from theirbulk values by about 41.7% and -21.5% as the film thickness isdown to 12.5nm. The atomic force microscope reveals that thesurface roughness the ultra thin metal film is about 6.0nm. Thedepolarization of this roughness seems not play as essentialrole in the ellipsometry determin- ation of the opticalconstant of thin metal films.