Gate-field-induced phase transitions in VO2: Monoclinic metal phase separation and switchable infrared reflections

In a metal-oxide-semiconductor VO2 active layer under uniaxial stress, gate- field- induced phase transitions are revealed by strongly field- dependent Raman scattering and infrared reflections. A metal- insulator transition (MIT) is demonstrated by a strongly correlated monoclinic metal phase separation that percolates, thereby making the reflections switchable. In addition, the MIT occurs at a gate voltage around 3.36 V, much lower than the threshold of a structural phase transition (SPT). Hence, the MIT is easily controlled by the gate field to avoid the SPT-caused fatigue and breakdown in high-speed operation. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3009569]