TITLE:
Preparation of Thin Films by a Bipolar Pulsed-DC Magnetron Sputtering System Using Ca3Co4O9 and CaMnO3 Targets
AUTHORS:
Weerasak Somkhunthot, Nuwat Pimpabute, Tosawat Seetawan
KEYWORDS:
Thermoelectric Thin Film; Ca3Co4O9; CaMnO3; Bipolar Pulsed-DC Magnetron Sputtering System
JOURNAL NAME:
Materials Sciences and Applications,
Vol.3 No.9,
September
27,
2012
ABSTRACT: The thin films were deposited on the glass substrates by an asymmetric bipolar pulsed-dc magnetron sputtering system using the Ca3Co4O9 and CaMnO3 Targets (n-type) targets of 60 mm diameter and 2.5 mm thickness. The targets were prepared from powder precursors, which obtained by a solid state reaction. Optical emissions from plasmas during sputter depositions of films were detected using a high resolution spectrometer. Thickness of thin film was estimated by Tolansky’s Fizeau fringe method and ellipsometic measurement. Crystal structures were studied from X-ray diffraction. The thermoelectric properties were assessed from Seebeck coefficient and electrical resistivity measurements at room temperature. The power factors were calculated. It was found that the optical emission spectrums showed that the Ca, Mn, Co and O atoms were sputtered from the targets onto glass substrates. As-deposited Ca-Co-O and Ca-Mn-O films thickness values were 0.435 ?m and 0.449 ?m, respectively. The X-ray diffraction patterns clearly showed amorphous nature of the as-deposited films. Determining thermoelectric properties of Ca-Co-O film gave Seebeck coefficient of 0.146 mV/K, electrical resistivity of 0.473Ω.cm, and power factor of 4.531 μW/m?K at room temperature. Ca-Mn-O film baring a high resistance was not the experimental determination of thermoelectric properties.