Abstract:
Vanadium dioxide (VO2), because of its unique metal–insulator phase transion around room temperature, has
enormous potential for applications in thermochromic, electrochromic, microbolometery, and non-volatile
switches. However, obtaining phase-pure VO2 has been challenging due to its narrow window of thermodynamic
stability. Pulsed laser deposition (PLD) is considered to be one of the most promising technique to deposit phasepure
VO2 thin films. While optimizing PLD processing parameters, (such as oxygen pressure (PO2), substrate
temperature (Ts), laser energy (EL), target-substrate distance (dT-S), and laser repetition rate (RR)) is crucial, and
their effects have been reported, the effect of gas flow rate (QO2) has been largely neglected. Since the QO2 and
PO2 of the PLD system are intertwined at the outset, most reports are focused only on either QO2 or PO2. We
report on the effect of gas flow rate under constant PO2, on the quality of the VO2 thin films. Controlling flow rate
affected the resistivity contrast between the metallic and insulator phases, the temperature ranges of the transition,
and the width of hysteresis. We anticipate that this study will help set the standard for obtaining high
quality VO2 thin films.
