Dissertation > Excellent graduate degree dissertation topics show

The Effect of Boron Doping on Optical Properties of β-SiC

Author: FengGuiYing
Tutor: FangXiaoYong
School: Yanshan University
Course: Condensed Matter Physics
Keywords: First-principles β-SiC B-doped Electronic structures Optical properties
CLC: TN304.24
Type: Master's thesis
Year: 2010
Downloads: 70
Quote: 0
Read: Download Dissertation

Abstract


Silicon Carbide (SiC) is a promising semiconducting material because of its excellent physical and electrical properities, such as the wide band gap, high electrical breakdown field, and high thermal conductivity and so on. However, because of its indirect band gap characteristic, the efficiency of photoelectric donversion is very low. Therefore, investing the modification of band gap is great significance. In recent years, with the deeping of theoretical research and experimental technology, researchers prove that the properties of SiC materials can be controlled through the incorporation of impurity.Based on the results of the newest study and a large number of references, we systemly study the heavily B-doped (1×1×1) and (2×2×2) SiC superecells numerically simulating the optical properties of optoelectronic materials, such as dielectric function, reflectivity, energy-loss, absorption and so on. The focuses are causes for the electronic structure and optical properties of undoped and doped SiC. The major work we have done is as follows:First, research status and development trends of SiC are clarified, and the significance of this paper is proposed. The application prospects and fundamental characteristics of SiC are introduced.Second, first-principles based on the density functional theory (DFT) are introduced, and the focal point is the pseudopotential theory. Then we present the CASTEP code in detail.Third, using CASTEP code calculate (1×1×1) and (2×2×2) zinc blende silicon carbide (β-SiC) after Carbon atom replaced by boron atom, and understand the effect of high doping concentration on the electrical structure and the optical properties. The calculated results show that after boron atom substitued Carbon atom the top of thevalence band of B-doped SiC are determined by B2p rather than C2p in SiC; the band gap ofβ-SiC transforms from indirect band gap to direct band gap with band gap shrink; the infrared absorption would intensify with the increase of doping concentration, and absorption edge emerges redshift; the dielectric constant of heavily B-dopedβ-SiC in lowfrequency is found to be remarkably largerFinally, boron on the Carbon and Silicon sites (BC and BSi) (2×2×1) supercellβ-SiC are investigated. Calculation results reveal that except for the difference of electric structures, both dielectric and conductivity spectra of BSi in the infrared region emerge remarkable peak yet BC is relatively flat.This is due to BC apply to Lorentz dispersion theory while BSi is following Drude dispersion theory.

Related Dissertations

  1. The Preparation and Thermoelectric Properties of Rare Earth Subsituted Ag Composite Ca3Co4O9-Based Oxides,TQ174.1
  2. Studies on Synthesis, Characterization and Properties of Fe-V Co-doped TiO2 Catalyst,O614.411
  3. First- principles calculations of doped anatase titanium dioxide photocatalytic properties,O643.36
  4. Of Bi N Co-doped TiO \u003csub\u003e 2 \u003c/ sub\u003e of the preparation and performance,O614.411
  5. Investigation of Fabrication, Characterization and Property of Fuctional Titanium Dioxide Nanoporous Materials,TB383.1
  6. Investigation of Preparation and Properties of Ordered Porous TiO2,TB383.2
  7. Iron-doped SnO \u003csub\u003e 2 \u003c/ sub\u003e ceramics and thin films research,TQ174.6
  8. First-Principles Studies of Blacl Phosphorus and LiMn2O4 as Electrode Material for Lithium Ion Batteries,TM912
  9. First-Principles Studies of Cathode Material LiMO2 （M=Co, Ni, Mn） of Lithium Ion Batteries,TM912
  10. Optical Properties of Chlorphyll-a in Reservoir Water and Its Concentration Inversion Models by Remote Sensing,S127
  11. Preparation of graphene Defects,O613.71
  12. Erbium-doped fiber amplifier pump laser drive source research applications,TN248
  13. Substrate microstrip bandpass filter parameters on the transmission characteristics of impact studies,TN713.5
  14. Eu- doped α-SiAlON phosphor First-principles study,TB34
  15. First-principles study of the structure and optical properties of the high-pressure alkali metal (Li, Na, K),O521.2
  16. Synthesis, Conformation and Character of W/Cu/S Supermolecule Clusters Containing Tp~* Group,O611.4
  17. Construction, Characterization and Properties of Tp~*-Containing W/S/Cu Clusters,O611.4
  18. First-principles Study on the Influence of Doping on the Strength of Super-hard Materials,O469
  19. Preparation and Luminous Property of Tm and Dy Doped YSZ Coating,TG174.442
  20. Based on the study of all-optical logic gates for fiber nonlinear effects,TN253
  21. Preparation and Properties of Non-hydrogenated Diomand-like Carbon and Non-hydrogenated Si-doped Diomand-like Carbon Films,TB383.2

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > General issues > Material > Compound semiconductor > Ⅳ - Ⅵ compound semiconductors
© 2012 www.DissertationTopic.Net  Mobile