Epitaxial (002) VO2 films were grown onto c-sapphire with Ga:ZnO and ZnO buffer layers. An investigation was made of the influence of twin boundaries upon the semiconductor-to-metal transition characteristics of VO2, when current flowed parallel and perpendicular to the twin boundaries. The structure of the twin boundary was kept the same for these two configurations. The hysteresis in semiconductor-to-metal transition characteristics was considerably reduced when current flowed parallel to the boundaries, as compared to that in the normal direction of the boundaries. A model was used to explain these observations and discuss the role of the boundaries in the semiconductor-to-metal transition characteristics.

Role of Twin Boundaries in Semiconductor to Metal Transition Characteristics of VO2 Films. T.H.Yang, C.Jin, H.Zhou, R.J.Narayan, J.Narayan: Applied Physics Letters, 2010, 97[7], 072101