Increase of Structural Phase Transition Temperature with Cr doping in Cr:VO$_{2}$ Thin Films

Bulk crystal VO$_{2}$ has a well-known structural phase transition near T$_{c} =$ 68 $^{\circ}$C that separates a low-temperature insulating phase from a high-temperature metallic phase with several orders-of-magnitude resistance contrast between the two phases. We report electrical and optical studies of the effect of Cr doping on the T$_{c}$ in Cr:VO$_{2}$ thin films. Resistivity, Hall effect, and infrared reflectivity all show that Cr doping systematically increases T$_{c}$ from 50 $^{\circ}$C up to $\sim$ 75 $^{\circ}$C at 11{\%} Cr with similar transition width and hysteresis from DC to infrared, but the effect appears to saturate. At the same time, there is a modest decrease in resistance contrast. We will discuss possible effects of both carrier density and scattering changes across T$_{c}$ on the resistance. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.