R. Subba Reddy; K. Radhamma; A. Sivasankar Reddy; S. Uthanna
Abstract
Thin films of molybdenum doped (2.7 at.%) zinc oxide (MZO) were deposited on glass substrates held at room temperature by RF magnetron sputtering of mosaic target of Mo-Zn at different substrate bias voltages. The influence of substrate bias voltage on the structural, electrical and optical properties ...
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Thin films of molybdenum doped (2.7 at.%) zinc oxide (MZO) were deposited on glass substrates held at room temperature by RF magnetron sputtering of mosaic target of Mo-Zn at different substrate bias voltages. The influence of substrate bias voltage on the structural, electrical and optical properties was investigated. The MZO films deposited on unbiased substrate were of amorphous, while those formed at substrate bias voltage of -40 V and above were of nanocrystalline. The crystallite size of the films improved with the applied bias voltage. At higher substrate bias voltage of -120 V the ion bombardment induced the high defect density in the films hence decrease in the crystallinity. The films formed at substrate bias voltage of -80 V exhibited low electrical resistivity of 1.2x10 -2 Ωcm and optical transmittance of about 79 %. These films showed optical band gap of 3.29 eV and figure of merit of 19 Ω -1 cm -1 .
R. Subba Reddy; A. Sreedhar; A. Sivasankar Reddy; S. Uthanna
Abstract
Zinc oxide (ZnO) thin films were formed by RF reactive magnetron sputtering onto p-type silicon and glass substrates held at room temperature. The thickness of the films deposited was in the range 160 – 398 nm. The thickness dependence structural, morphological and optical properties of ZnO films ...
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Zinc oxide (ZnO) thin films were formed by RF reactive magnetron sputtering onto p-type silicon and glass substrates held at room temperature. The thickness of the films deposited was in the range 160 – 398 nm. The thickness dependence structural, morphological and optical properties of ZnO films were systematically investigated. The maximum crystallite size of 21 nm observed at films thickness of 231 nm by X- ray diffraction. Scanning electron microscopic analysis revealed that the growth of nanowires in all the films. The root mean square roughness of the films increased from 7.3 to 53 nm in the thickness range of investigation. Fourier transform infrared analysis confirmed the Zn-O bonding located at wavenumber of 413 cm -1 . The average optical transmittance of the films was about 89 % in the visible region. The optical band gap of the ZnO films decreased from 3.14 to 3.02 eV with increase of film thickness from 160 to 398 nm respectively.