Study the electronic properties of CdTe nanostructure

Other Title(s)

دراسة الخصائص الإلكترونية لتركيب CdTe النانوني

Dissertant

al-Hasan, Hamid Ahmad Fayyd

Thesis advisor

Husayn, Muhammad Taqi

Comitee Members

al-Ias, Maysun F. A.
Amin, Hamid M.
Rashid, Bassam Ghalib

University

University of Baghdad

Faculty

College of Science

Department

Department of Physics

University Country

Iraq

Degree

Master

Degree Date

2013

English Abstract

Gaussain 03 code of Ab-initio Density functional theory (DFT) coupled with large unit cell method is used to determine the electronic structure properties of II-VI zinc blende cadmium tellurium (CdTe) at nanocrystals size (8,16,54 and 64) of core atoms for 3D periodic boundary condition (PBC) and 2D (PBC) calculation were used to simulated oxygenated (001)-(1x1) surface.

The crystal length was between 1.93- 2.54 nm.

In present work it has investigated properties include the total energy , cohesive energy , energy gap , valence and conduction bands width , ionicity and degeneracy of states for core and surface parts.

The results obtained show that the total energy and cohesive energy of CdTe nanocrystals decreases with increasing the size of core atoms and this cause a decrease of lattice constant respectively, and the lattice constant for the surface part is smaller than of core part.

The ionicity of the core part decreases with increasing number of core atoms.

The energy gap of core part at the size of 8 core atoms is about 3.33 eV compare with the energy gap for surface part with the same size which is equal 0.136 eV.

The valence and conduction bands width increase with increasing number of core atoms , while conduction band width is wider on the surface.

The results also show that the density of states increases with increasing the number of core atoms, and the density of states of core part is higher than that at surface part, this is due to the broken symmetry at the surface discontinuity and existence of new kind of atoms (oxygen atoms).

Generally, the results obtained from ab-initio method in the present work are in good agreement with others theoretical and experimental studies.

Main Subjects

Physics

Topics

• Electrical properties
• Solids
• Semiconductors

No. of Pages

78

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-606959