Growth and phase transition properties of Ta-doped VO2 single crystal microtubes

Ta-doped VO2 single crystal microtubes with rectangular cross-sections were grown by a thermal oxidation process from V–Ta alloy foils in air. Characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy revealed their morphology as hollow, rod-like single crystals. Phase transition examinations used differential scanning calorimetry demonstrated that Ta doping can effectively decrease the metal-insulator transition temperatures of VO2 by approximately 9.8 °C/at. % Ta. The phase transition behavior and growth mechanism of Ta-doped VO2 single crystal microtubes are also elucidated. •Ta-doped VO2 single crystal microtubes were fabricated.•Ta doping can decrease the metal-insulator transition temperature of VO2 by approximately 9.8 °C/at. % Ta.•The phase transition route and mechanism of Ta-doped VO2 single crystal microtubes are revealed.