VO2 multidomain heteroepitaxial growth and terahertz transmission modulation

We report the epitaxial relationship of VO2 thin-films on c-plane sapphire and their terahertz transmission modulation with temperature. The films exhibit a triple-domain structure caused by the lattice mismatch between monoclinic VO2 and sapphire hexagon. The epitaxial relationship is determined to be VO2[010]parallel to Al2O3[0001] and VO2((2) over bar 02)parallel to Al2O3{11 (2) over bar0}, with the in-plane lattice mismatch of 2.66% (tensile) along [(2) over bar 02] and the out-of-plane lattice mismatch of -2.19% (compressive). Terahertz measurements revealed that VO2 films have over fourfold change in transmission during the metal-insulator transition, indicating a strong potential for terahertz wave switching and modulation applications. (C) 2010 American Institute of Physics. [doi:10.1063/1.3519361]