QUANTUM SIZE EFFECTS IN CDS THIN-FILMS
QUANTUM SIZE EFFECTS IN CDS THIN-FILMS
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DOI：
10.1103/physrevb.45.11805
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发表时间：
1992-05-15
影响因子：
3.7
通讯作者：
DAI, CM
中科院分区：
文献类型：
--
作者：
CHUU, DS;DAI, CM
利用共振喇曼光谱研究了硫化镉薄膜的量子尺寸效应。观察到厚度小于800埃的硫化镉薄膜中的硫化镉低声子模的晶格软化现象。当薄膜厚度小于410埃时，在4880埃激发波长观察到声子模，该波长高于体相硫化镉的禁带宽度(2.42 eV)。这些现象归因于颗粒尺寸和低维薄膜结构的尺寸量子化效应。量子尺寸效应导致了沉积的CdS薄膜的带隙蓝移。观察到硫化镉薄膜的声子模拉曼峰位于220 cm-1附近，与块体硫化镉最活跃的声子模的拉曼线相差8 cm-1。观察到声子模软化能的大小与薄膜厚度无关。
Resonant Raman spectroscopy is used to study quantum size effects in CdS films. The lattice softening of the CdS LO-phonon mode in a CdS film with a thickness less than 800 angstrom is observed. As the thickness is less than 410 angstrom, the TO-phonon mode is observed at 4880 angstrom excitation wavelength, which is above the band gap of bulk CdS (2.42 eV) at room temperature. These phenomena are attributed to the size quantization effects of the grain size and the low-dimensional thin-film structure. The quantum size effects cause a blueshift of the band gap in the as-deposited CdS thin film. The peak of the TO-phonon-mode Raman line of the CdS film is observed around 220 cm-1, which has a shift of 8 cm-1 from the Raman line of the most active TO-phonon mode of bulk CdS. The magnitude of softening energy of the TO-phonon mode is observed to be independent of the film thickness.