Effect of Al2O3 Buffer Layers on the Properties of Sputtered VO2 Thin Films

VO 2 thin films have generated a considerable interest among scientists over the past decades owing to their near-room-temperature phase transformation [ 1 ]. VO 2 thin films undergo transition from a reversible monoclinic (M phase) to a rutile (R phase) structural phase at approximately 65 °C, which is accompanied by a dramatic change in their electrical and optical properties [ 2 – 6 ]. The resistivity of VO 2 thin films changes by three to five orders of magnitude during this phase transition. The metal-to-insulator (MIT) transition has been utilized in a variety of electronic devices such as electromagnetic wave modulators, switches [ 7 – 10 ], and holographic storage [ 11 ]. So far, the applications of VO 2 thin films have been mainly explored for infrared and millimeter waves [ 10 , 12 ]. Recently, VO 2 thin films have been used for terahertz (THz)-wave devices [ 7 ]. In 2010, VO 2 nanowires were deposited on glass substrates using photolithography and magnetron sputtering and used for the thermal modulation of THz waves by Wen et al. [ 7 ]. The research results showed that the transmittance of THz waves reduced by 65% after traveling through VO 2 nanowire arrays during the MIT transition [ 7 ].