Fabrication of smooth thin film of vanadium oxides ($$\hbox {VO}_x$$) using pulsed laser deposition

Abstract

We report the synthesis of vanadium oxide thin films by the pulsed laser deposition under different parameter conditions on $$\hbox {Si/SiO}_2$$ substrates using $$\hbox {V}_2\hbox {O}_5$$ target. The objective of the present work was to achieve smooth $$\hbox {VO}_2$$ thin film in a single step. Synergistic effect of the deposition parameters on the phase of vanadium oxides is studied by a series of experiments designed using Taguchi analysis. Conditions for depositing different oxides of vanadium like $$\hbox {VO}_2$$, $$\hbox {V}_2\hbox {O}_3$$, $$\hbox {V}_3\hbox {O}_5$$ and a new phase, $$\hbox {V}_7\hbox {O}_{16}$$ was established. The range of parameters varied were: gas pressure: $$10^{-3}$$–5 $$\times$$ $$10^{-2}$$ mbar; temperature: 500–700 $$^\circ$$C; target-substrate distance: 30–40 mm and laser energy: 100–200 mJ. $$\hbox {VO}_2$$ film with surface roughness of 3.68 nm having a semiconductor-to-metal transition (SMT) at 72 $$^\circ$$C with 2–3 orders of resistance change was achieved. Taguchi model was statistically analyzed to determine the suitable condition as well as effect of deposition parameters to obtain phase pure $$\hbox {VO}_2$$ thin film. The optimum condition for deposition was found to be: gas pressure: 5 $$\times$$ $$10^{-2}$$ mbar; temperature: 600 $$^\circ$$C; distance: 35 mm, and laser energy: 200 mJ after analyzing using Taguchi model.