Investigation of electron beam lithography effects on metal-insulator transition behavior of vanadium dioxide

İngilizce (OpenAlex)

Abstract Vanadium dioxide (VO 2 ) shows metal–insulator phase transition at nearly 68 °C. This metal–insulator transition (MIT) in VO 2 leads to a significant change in near-infrared transmittance and an abrupt change in the resistivity of VO 2 . Due to these characteristics, VO 2 plays an important role on optic and electronic devices, such as thermochromic windows, meta-materials with tunable frequency, uncooled bolometers and switching devices. In this work, VO 2 thin films were fabricated by reactive direct current magnetron sputtering in O 2 /Ar atmosphere on sapphire substrates without any further post annealing processes. The effect of sputtering parameters on optical characteristics and structural properties of grown thin films was investigated by SEM, XRD, Raman and UV/VIS spectrophotometer measurements. Patterning process of VO 2 thin films was realized by e-beam lithography technique to monitor the temperature dependent electrical characterization. Electrical properties of VO 2 samples were characterized using microprobe station in a vacuum system. MIT with hysteresis behavior was observed for the unpatterned square samples at around 68 °C. By four orders of magnitude of resistivity change was measured for the deposited VO 2 thin films at transition temperature. After e-beam lithography process, substantial results in patterned VO 2 thin films were observed. In this stage, for patterned VO 2 thin films as stripes, the change in resistivity of VO 2 was reduced by a factor of 10. As a consequence of electrical resistivity measurements, MIT temperature was shifted from 68 °C to 50 °C. The influence of e-beam process on the properties of VO 2 thin films and the mechanism of the effects are discussed. The presented results contribute to the achievement of VO 2 based thermochromic windows and bolometer applications.