Investigation of phase evolution and control over phase transformation temperature and thermal hysteresis using stoichiometry and co-doping in VO2 thin films

Abstract

Structural phase transition temperature and its associated hysteresis in VO2 have been controlled by high valent dopant induced local structural modification which acts as phase nucleation site during phase transformation. Monoclinic phase intensity loops plotted against temperature has been observed to exhibit thermal hysteresis. It is shown that the size, shape and central position of hysteresis loop depend on stoichiometry and doping concentration. Highest reduction in phase transformation temperature and thermal hysteresis width has been observed in case of W+6-Mo+6 co-doping and W+6 doping, respectively. Hence energy barrier associated with the structural phase transition has been successfully manipulated to vary Tc and hysteresis width. These findings have implications for designing the phase switching devices and smart window applications.