Investigation of the optical properties of silicon solar cell component materials

Normal incidence reflectance data and optical constants of silicon and germanium extrapolated to maximum and minimum limit

Investigation of the optical properties of silicon solar cell component materials Final report

Optical properties of silicon solar cell component materia

Research on the mechanism and kinetics of oxidation of silicon in air Semiannual report, 1 Dec. 1966 - 31 May 1967

Mechanism and kinetics of silicon oxidation in air-instrumentation for ellipsometry and use in determining refractive index and thickness of thin oxide films on silico

Research on the mechanism and kinetics of oxidation of silicon in air Semiannual report, 1 Dec. 1967 - 31 May 1968

Ellipsometric method for measuring optical parameters of substrate and oxidation surface layer thickness on silico

Research on the Mechanism and Kinetics of Oxidation of Silicon in Air Semiannual Report, 1 Jun. - 30 Nov. 1966

Ellipsometric studies on mechanism and kinetics of thin oxide films on silicon in ai

Research on the Mechanism and Kinetics of Oxidation of Silicon in Air Second Semiannual Report, 1 Dec. 1965 - 31 May 1966

Ellipsometer studies of oxide thin film growth on silicon in ai

Ion-implantation induced anomalous surface amorphization in silicon

Spectroscopic ellipsometry (SE), high-depth-resolution Rutherford 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

The ResQu Index: A new instrument to appraise the quality of research on birth place

© 2017 Vedam et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Objective: Place of birth is a known determinant of health care outcomes, interventions and costs. Many studies have examined the maternal and perinatal outcomes when women plan to give birth in hospitals compared with births in birth centres or at home. However, these studies vary substantially in rigour; assessing their quality is challenging. Existing research appraisal tools do not always capture important elements of study design that are critical when comparing outcomes by planned place of birth. To address this deficiency, we aimed to develop a reliable instrument to rate the quality of primary research on maternal and newborn outcomes by place of birth. Study design: The instrument development process involved five phases: 1) generation of items and a weighted scoring system; 2) content validation via a quantitative survey and a modified Delphi process with an international, multi-disciplinary panel of experts; 3) inter-rater consistency; 4) alignment with established research appraisal tools; and 5) pilot-testing of instrument usability. Results: A Birth Place Research Quality Index (ResQu Index) was developed comprising 27 scored items that are summed to generate a weighted composite score out of 100 for studies comparing planned place of birth. Scale content validation indices were .89 for clarity, .94 for relevance and .90 for importance. The Index demonstrated substantial inter-rater consistency; pilot-testing confirmed feasibility and user-friendliness. Conclusion: The ResQu Index is a reliable instrument to evaluate the quality of design, methods and interpretation of reported outcomes from research about place of birth. Higher-scoring studies have greater potential to inform evidence-based selection of birth place by clinicians, policy makers, and women and their families. The Index can also guide the design of future research on place of birth

Ion-implantation-caused special damage profiles determined by spectroscopic ellipsometry in crystalline and in relaxed (annealed) amorphous silicon

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

Photoelasticity of crystalline and amorphous silica from first principles

Based on density-functional perturbation theory we have computed from first principles the photoelastic tensor of few crystalline phases of silica at normal conditions and high pressure (quartz, $\alpha$-cristobalite, $\beta$-cristobalite) and of models of amorphous silica (containig up to 162 atoms), obtained by quenching from the melt in combined classical and Car-Parrinello molecular dynamics simulations. The computational framework has also been checked on the photoelastic tensor of crystalline silicon and MgO as prototypes of covalent and ionic systems. The agreement with available experimental data is good. A phenomenological model suitable to describe the photoelastic properties of different silica polymorphs is devised by fitting on the ab-initio data.Comment: ten figure