Open Access Research Article Issue
Crystallization and inter-diffusional behaviors in the formation of VO2(B) thin film with layered W-doping
Journal of Advanced Ceramics 2017, 6 (3): 196-206
Published: 29 September 2017

To achieve a better material for uncooled infrared (IR) detector, polycrystalline VO2(B) thin films with layered W-doping were fabricated on Si substrates by magnetron sputtering, and the best temperature coefficient of resistance (TCR) value reached -4.1%/K. The film synthesis was in a two-step route, first deposition at room temperature and then post-deposition annealing at 450 ℃, to better control the crystallization behavior. Various transmission electron microscopy (TEM) methods were employed to investigate three sets of multi-layered films with different deposition time, 10, 20, and 30 min, with especial emphasis on the effect of layered W-doping scheme on the formation of multiple VO2(B) layers. Spatial-resolved energy dispersive X-ray spectroscopy (EDS) revealed the alternative patterns of W-rich layers and W-poor layers, while the thinner films exhibited better crystallinity and texturing. By comparison with an as-deposited film, it was found that the inter-diffusion between the two types of layers was completed in the deposition step while both remained in amorphous structure. A stable W solution of about 8 cat% in VO2(B) layers measured from all these films indicated that the layered doping can tailor the multi-layered microstructure to optimize the performance of VO2(B) films.

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