Thin film epitaxy and near bulk semiconductor to metal transition in VO₂/NiO/YSZ/Si(001) heterostructures

We have grown VO2/NiO epitaxial thin films by pulsed laser deposition where integration with Si(001) substrates was achieved by cubic yttria-stabilized zirconia (YSZ) buffer layer. The most interesting aspect of this work is that a complete relaxation alongc-axis of VO2is achieved in these large misfit systems through the domain matching epitaxy paradigm, which is critical for controlling the semiconductor to metal transition (SMT) characteristics. Regarding x-ray diffraction and cross-sectional transmission electron microscopy results, the epitaxial relationship across the YSZ/Si(001) interface was (001)[100]YSZ(001)[100]Si. In the case of YSZ/NiO interface, the epitaxial relationship was (001)[010]YSZ⋎(111)[001]NiO. The epitaxial relationship at the NiO/VO2interface was determined to be (010)[001]VO2⋎(111)[001]NiO. The SMT characteristics of these fully relaxed films were determined, and a transition temperature of 341 K. with amplitude over four orders of magnitude and the hysteresis of 3.4 K. hysteresis were obtained, which are close to those of the bulk high quality single crystals.