The effects of carbon content on the properties of plasma deposited amorphous silicon carbide thin films

Download

index.pdf

Date

2007

Author

Sel, Kıvanç

Metadata

Show full item record

Item Usage Stats

239
views

199
downloads

The structure and the energy band gap of hydrogenated amorphous silicon carbide are theoretically revised. In the light of defect pool model, density of states distribution is investigated for various regions of mobility gap. The films are deposited by plasma enhanced chemical vapor deposition system with various gas concentrations at two different, lower (30 mW/cm2) and higher (90 mW/cm2), radio frequency power densities. The elemental composition of hydrogenated amorphous silicon carbide films and relative composition of existing bond types are analyzed by x-ray photoelectron spectroscopy measurements. The thicknesses, deposition rates, refractive indices and optical band gaps of the films are determined by ultraviolet visible transmittance measurements. Uniformity of the deposited films is analyzed along the radial direction of the bottom electrode of the plasma enhanced chemical vapor deposition reactor. The molecular vibration characteristics of the films are reviewed and analyzed by Fourier transform infrared spectroscopy measurements. Electrical characteristics of the films are analyzed by dc conductivity measurements. Conduction mechanisms, such as extended state, nearest neighbor and variable range hopping in tail states are revised. The hopping conductivities are analyzed by considering the density of states distribution in various regions of mobility gap. The experimentally measured activation energies for the films of high carbon content are too low to be interpreted as the difference between Fermi level and relevant band edge. This anomaly has been successfully removed by introducing hopping conduction across localized tail states of the relevant band. In other words, the second contribution lowers the mobility edge towards the Fermi level.

Subject Keywords

Physics., Optical constants.

URI

http://etd.lib.metu.edu.tr/upload/2/12608292/index.pdf
https://hdl.handle.net/11511/17239

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Density functional theory investigation of TiO2 anatase nanosheets Sayın, Ceren Sibel; Toffoli, Hande; Department of Physics (2009) In this thesis, the electronic properties of nanosheets derived from TiO2 anatase structure which acts as a photocatalyst, are investigated using the density functional theory. We examine bulk constrained properties of the nanosheets derived from the (001) surface and obtain their optimized geometries. We investigate properties of lepidocrocite-type TiO2 nanosheets and nanotubes of different sizes formed by rolling the lepidocrocite nanosheets. We show that the stability and the band gaps of the considered ...
THE EFFECT OF A 3RD COMPONENT IMPURITY-C ON THE HEAT-CAPACITY OF A3B-TYPE ORDERED ALLOYS Mehrabov, Amdulla; MATYSINA, ZA (Wiley, 1989-12-01) For the first time theoretical (in terms of the classical theory of ordering) and experimental (with the adiabatic calorimeter method) investigations are made of the effect of a third component impurity C on the heat capacity of A3B‐type ordered alloys with FCC structure. The effect of the impurities Mn, Cr, Mo, or W on the heat capacity of Ni3Fe alloys is analysed as an example. The comparison of the theoretical results with the experimental data shows good qualitative agreement.
The controlled drift detector as an x-ray imaging device for diffraction enhanced imaging Özkan, Çiğdem; Serin, Meltem; Department of Physics (2009) Diffraction Enhanced Imaging (DEI) is an X-ray imaging technique providing specific information about the molecular structure of a tissue by means of coherently scattered photons. A Controlled Drift Detector (CDD) is a novel 2D silicon imager developed to be used in X-ray imaging techniques. In this work a final (complete and detailed) analysis of DEI data taken with the CDD in the ELETTRA synchrotron light source facility in Trieste (Italy) in 2005, is presented and the applicability of both this new techn...
The investigation of electronic, anisotropic elastic and lattice dynamical properties of MAB phase nanolaminated ternary borides: M 2 AlB 2 ( M = Mn , Fe and Co ) under spin effects Surucu, Gokhan; YILDIZ, BUĞRA; Erkisi, Aytac; Wang, Xiaotian; Surucu, Ozge (Elsevier BV, 2020-10-01) In the present study, the structural, electronic, magnetic, anisotropic elastic and lattice dynamic properties of the ternary metal borides (, and ) known as MAB phases have been investigated by density functional theory. The obtained results from the structural optimizations show that all these compounds have negative formation enthalpy implying the thermodynamic stability and synthesizability. The spin effects on the phases have been studied with the plotted energy-volume curves for different magnetic pha...
Effects of boron doping on solid phase crystallization of in situ doped amorphous Silicon thin films prepared by electron beam evaporation Sedani, Salar H.; Yasar, Ozlen F.; Karaman, Mehmet; Turan, Raşit (Elsevier BV, 2020-01-31) In this work, we studied solid-phase crystallization of boron-doped non-hydrogenated amorphous Si films fabricated by electron beam evaporation equipped with effusion cells (e-Beam EC) on silicon nitride coated glass substrates. We investigated the effect of boron doping on the crystallization kinetics through a series of experiments with different boron doping concentrations controlled by the effusion cell temperature. We employed Raman spectroscopy, time-of-flight secondary ion mass spectroscopy, grazing ...

Citation Formats

K. Sel, “The effects of carbon content on the properties of plasma deposited amorphous silicon carbide thin films,” Ph.D. - Doctoral Program, Middle East Technical University, 2007.