The nucleation of thin-film amorphous silicon (a-Si), sputter deposited on oxidized c-Si, is investigated by real-time spectroscopic ellipsometry from 1.5 to 4.5 eV with a resolution of 3 s and a repetition period of 15 s. Analysis of real-time spectra provides unprecedented sensitivity and quantitative information on the microstructural evolution. Under preparation conditions resulting in a-Si of the highest bulk Si-Si bond-packing density, an abrupt transition representing the onset of bulk film growth can be identified unambiguously when nuclei reach a thickness of 13 ± 1 A.
The composition and structure of crystalline silicon implanted with carbon ions at high dose were studied using spectroscopic ellipsometry. A brief description of our spectroscopic ellipsometer system and the modeling method adopted for the analysis of the data are included. The crystal damage caused by carbon-ion implantation in the as-implanted sample was characterized as an amorphous region of atomic or chemical mixture of silicon and carbon atoms. The recrystallization of Si and the formation of crystalline silicon carbide on annealing these specimens at 800 °C and 1000 °C were investigated through similar spectroscopic ellipsometry studies.
The primarily qualitative analysis reported in this paper is to investigate how the students, in a student-centered pedagogical focus, perceive their own learning progress in e-peer feedback activities, including the effectiveness of the use of blogs for e-peer responses in an L2 writing class. Thirty-two second year Vietnamese students at a university in Ho Chi Minh City participated in a 15-week writing course. Data collection was from the 20-item questionnaire and eight semi-structured interviews. Results of the study revealed that when students perceived good progression in their writing skills when they got involved in e-peer feedback on the blog and their writing was longer after revisions. In addition, the students highly evaluated the use of blogs for e-peer feedback activities because of its usefulness and effectiveness.
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