Study the thermoelectric and characterization of Sn, Zn, thin films prepared by the oblique angle deposition

مقدم أطروحة جامعية

Khalaf, Wafa Khalid

مشرف أطروحة جامعية

Jawad, Muslim Fadil
Musa, Ali M.

الجامعة

الجامعة التكنولوجية

الكلية

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القسم الأكاديمي

قسم العلوم التطبيقية

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

-In this work, oblique angle deposition technique (OAD) was used to deposit tin and zinc thin films at different deposition angle (◦0 , ◦50 , ◦60 , ◦70 and ◦80 ) by vaccum evaporation with resistive heating technique and carry out a basic characterization of the structure , optical and electrical properties of these thin films as a function of deposition angle (◦Ө).Thickness measurement showed that the thickness of deposited film decreases very sharply for high deposition angle (◦Ө>˚50), while having a small change at all angles less than (◦Ө<◦50), this is due to oblique geometrical consideration.

The AFM results reveal an increase in the film's roughness from (33.7 to 39.2) nm and from (12 to 59) nm for zinc and n thin films respec vely when ◦ Ө changes from ◦0 to ◦80 .Root mean square roughness (RMS roughness) also was found to increase with increasing deposition angle.

Reflection microscope results showed that the smoothness and homogeneity of the films decrease with increasing deposition angle ◦Ө، and the surface roughness increases with increasing angle for both metallic films.

The results of varying the incidence angle from normal to off normal ( from 0◦to80◦) for tin and zinc thin films indicate that all films are polycrystalline with tetragonal and hexagonal wurtzite structure, and the highest diffraction peak accompanys films deposited at angle (˚70) for both metallic films.Also it was found that there is enhancement in the inter plane spacing (d) in films obliquely deposited as compared with normal films (this refers to small strength in the interplane distance in oblique incidence as compared with normal incidence).

Some structural properties such as grain size, micro strain, shape factor, number of layers, lattice constant and texture coefficients as a function of deposition angle were calculated for both metallic films.The optical transmission for tin (Sn) and zinc (Zn) films at the range (350-900) nm were found to be dependent on the deposi on angle (◦Ө).

It was found the average transmittance for the two materials in UV-VIS region decrease with both increases in wave length and deposition angle.

It was found that at wave length (550) nm, the transmi ance decreases by factors (3.6, 2.5) for n and zinc thin film respec vely, when angle increases from ◦50to ◦80.

In addition to this, increase in deposition angle led to decrease in the electrical conductivity.

It was found that the dark conduc vity decreases from 7.5×104 to1.5 ×104 (Ω cm)−1 and from (4 *104 to 0.81*104 ) (Ω cm)−1when deposition angle increases from 0◦ to 80◦ for zinc and tin thin film respectively and I-V characteristic at dark condition showed a linear behavior following ohms law.

Also it was found from dark conductivity, dependence on temperature in normal (◦Ө =◦0( and off normal (◦Ө=◦80) deposited films, It is a decreasing function of temperature, increase for two angles for both metallic films.

The thermoelectric properties revealed a dependence on deposition angle.

From obtained results; it was found that the Seebeck coefficient(S), Figure of Merit (Z), and Power Factor (PF) have dependence on deposition angle (◦Ө).

It was found that the thermoelectric power (Seebeck coefficient) has the same value for angles less than ◦Ө <◦60 , then increases sharply for higher angles ◦Ө >◦60 for tin thin film, while in zinc thin films, it is accompanied by increasing thermoelectric power with increasing deposition angle.

Also it was found that the thermoelectric power (Seebeck coefficient) decreases with increasing film thickness, and having lower value at thickness 300nm (normal incidence), and increasing temperature (T) led to increase in thermoelectric power (Seebeck coefficient) for both metallic films.

Also it was found that there is linear increase in the figure of merit (Z) and power factor (PF) with deposition angle increase in zinc thin film, while in tin thin films, they decrease very sharply with deposition angle less than (◦Ө<◦60 ), then slightly increase with increasing angle.

التخصصات الرئيسية

هندسة المواد والمعادن

الموضوعات

• الخواص الكهربائية
• الخواص الضوئية
• المعادن

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305054