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.

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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.

Combination the materials together is a direct and forceful strategy to improve the electrochemical properties of each raw material. Herein, we present the method of hydrothermal process and treatment/calcination combination that is easy to synthesize a NiCo2O4 nanoparticles‐mesoporous carbon composite (C/NiCo2O4). The result study electrochemical properties of materials revealed that the C/NiCo2O4 composite has excellent electrochemical properties compare with pristine NiCo2O4 or carbon. In particular, maximum specific capacitance of C/NiCo2O4 material at a current density of 1 A.g−1 is 204.28 F.g−1, meanwhile the Cs of carbon and NiCo2O4 are 25.06 F.g−1 and 178.78 F.g−1, respectively. In addition, C/NiCo2O4 material also showed excellent capacitance retention, Cs maintained to 90.35% after 3000 charge‐discharge continuous cycles. The results show that the C/NiCo2O4 is a promising material for application as supercapacitor electrode.

Spectroscopic ellipsometry (SE), high-depth-resolutionRutherford backscattering (RBS) and channeling have been used to examine the surface damage formed by room temperature N and B implantation into silicon. For the analysis of the SE data we used the conventional method of assuming appropriate optical models and fitting the model parameters (layer thicknesses and volume fraction of the amorphous silicon component in the layers) by linear regression. The dependence of the thickness of the surface-damaged silicon layer (beneath the native oxide layer) on the implantation parameters was determined: the higher the dose, the thicker the disordered layer at the surface. The mechanism of the surface amorphization process is explained in relation to the ion beam induced layer-by-layer amorphization. The results demonstrate the applicability of spectroscopic ellipsometry with a proper optical model. RBS, as an independent cross-checking method supported the constructed optical model.

We previously developed a fitting method of several parameters to evaluate ion-implantation-caused damage profiles from spectroscopic ellipsometry (SE) (M. Fried et al., J. Appl. Phys., 71 (1992) 2835). Our optical model consists of a stack of layers with fixed and equal thicknesses and damage levels described by a depth profile function (coupled half Gaussians). The complex refractive index of each layer is calculated from the actual damage level by Bruggeman effective medium approximation (EMA) using crystalline (c-Si) and amorphous (a-Si) silicon as end-points. Two examples are presented of the use of this method with modified optical models. First, we investigated the surface damage formed by room temperature B + and N ÷ implantation into silicon. For the analysis of the SE data we added a near surface amorphous layer to the model with variable thickness. Second, we determined 20 keV B + implantation-caused damage profiles in relaxed (annealed) amorphous silicon. In this special case, the complex refractive index of each layer was calculated from the actual damage level by the EMA using relaxed a-Si and implanted a-Si as end-points. The calculated profiles are compared with Monte Carlo simulations (TRIM code); good agreement is obtained.