Structural and Morphological Study of VO₂ Thin Films Synthesized by RF Magnetron Sputtering
on Glass Substrates
Dawn Jade C. Curaya*,Hamdi Muhyuddin Barra b, Caironesa P. Dulpina b, Rayno Vic B. Janayon b,
Johnny Jim S. Ouanob
a
College of Mathematics, Arts and Sciences , Davao del Sur State College
Tablizo Avenue, Matti, 8002 Digos City, Davao del sur, Philippines
b
Department of Physics, Mindanao State University- Marawi
9700 Marawi City, Lanao del Sur, Philippines
Vanadium dioxide (VO₂) thin films are of significant interest for energy-efficient smart window
applications due to their tunable structural and optical properties [1]. The thermochromic monoclinic
phase (VO₂(M)) undergoes a reversible semiconductor–metal transition near 68 °C, enabling passive solar
modulation in buildings and vehicles [2,3]. However, the crystal phase and morphology of VO₂ thin films
are strongly influenced by deposition parameters such as oxygen (O₂) concentration, substrate type, and
growth temperature[4]. In this study, VO₂ thin films were synthesized on glass substrates using radio
frequency (RF) magnetron sputtering to investigate the effect of varying O₂ concentration on their
structural and morphological properties.
Thin films were deposited using radio frequency (RF) magnetron sputtering from a high-purity
vanadium target under three O2 concentrations (10%, 20%, and 30% O₂) in an Ar–O₂ mixture. Structural
characterization was performed using X-ray diffraction (XRD). Surface morphology, particle size
distribution, and roughness parameters were analyzed using atomic force microscopy (AFM)
XRD analysis showed that the films were mainly amorphous, exhibiting diffraction peaks
characteristic of the tetragonal VO₂(A) phase (JCPDS 98-007-8277) in all samples. At 10% O₂
concentration, the (020) plane had crystallite size of 24.4 nm. At 20% O₂, the (004) planes had crystallite
sizes of 43.0 nm. At 30% O₂, the (121) plane had crystallite size of 85.1 nm. AFM results revealed that
particle diameters increased from 33.99 nm (10% O₂) to 91.09 nm (30% O₂), with corresponding
increases in average height (8.75 nm to 24.32 nm) and the average roughness (2.603 nm to 3.88 nm).
Surface morphology transitioned from relatively uniform (10% O₂) to more varied and coarser textures
(30% O₂). These results show that increasing oxygen concentration promotes larger crystallite and
particle sizes, especially along the (121) plane, influencing VO₂ thin film optical and thermochromic
properties. The findings contribute to the optimization of VO₂-based smart window coatings for enhanced
energy efficiency.
The authors gratefully acknowledge the support of DOST-STRAND, Mindanao State University–
Marawi, and Davao del Sur State College.
[1] N. Shen et. al. Mater. Today Energy, 100827 (21) 2021
[2] D. Ruzmetov et.al J. Appl. Phys., 111 (102) 2007
[3] P. Jin et al. Appl. Phys. A, 455 (77) 2003
[4] D. Bhardwaj et al. J. Appl. Phys., 135301 (124) 2018.
Keywords: VO2 thin films, RF magnetron sputtering, O2 concentration, VO₂(A) phase and Smart
window materials
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* dawnjade.curay@dssc.edu.ph