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|Title:||Effects of temperature and deposition time on the structural and optical properties of Si1−xGex nanoparticles grown by low pressure chemical vapor deposition|
|Abstract:||The structural and optical properties of Si-1 -Ge-x(x) nanoparticles were studied in this work. The samples were grown by the low pressure chemical vapor deposition technique at different temperatures and deposition times. From the measurements of Raman spectroscopy, the strain (epsilon) and percentage of germanium (x) present on the samples were determined, using equations that describe the Si-Si, Si-Ge and Ge-Ge Raman vibrational modes. In all cases, an increase of the percentage of Ge as well as a decrease in the strain is observed with the increase of both temperature and deposition time, being this behavior more significant for samples grown for 30 s. The refractive index was obtained by ellipsometry. An increase of this parameter is observed with the increase of the percentage of Ge present on the samples as well as the increase of the density of nanoparticles. Photoluminescence measurement showed a band between 400 and 600 nm at room temperature, which could be attributed to Ge oxygen deficient centers. The best result was obtained for the sample Si0.79Ge0.21 grown at 650 degrees C during 30 s, with a nanoparticle mean-size of 32.9 nm, a density of 4.9 x 10(11) cm(-2), a refractive index of n-3.127 for a wavelength of lambda-632.9 nm and a luminescence peak at 2.6 eV (476 nm) at room temperature|
Deposição química de vapor
|Appears in Collections:||FEEC - Artigos e Outros Documentos|
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