1UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Pretoria-South Africa
2Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Somerset West, Western Cape Province, South Africa
Being a Mott/Peierls type oxide, at a temperature of about 68°C and ambient pressure, stoichiometric VO2 undergoes a first order metal-insulator transition, which is accompanied by a femtosecond structural transition from a high-temperature rutile to a low-temperature monoclinic phase. This reversible phenomenon causes an abrupt and significant change in the resistivity over several orders of magnitude induced by the band gap opening/closure. From optical point of view, this metalsemiconductor transition is accompanied by a significant and reversible variation of the refractive index under thermal stimuli in the infrared spectral range. Hence, VO2 based coatings have been attracting considerable interest for fundamental reasons, and certainly for technological applications in the solar energy sector and ultrafast linear and nonlinear photonics as well as opto-electronics. In this contribution, specific opto-electronic multi-functionality of nanostructured VO2 based coatings is presented. This includes applications such as (i) Active coating for solar heat management in buildings and automotives as a smart window, (ii) Tunable emissivity based coatings for satellites applications, (iii) Ultrafast opto-electronic gating, (iv) Optical limiting, (v) Femtosecond tunable nano-plasmonics in addition to room temperature H2 gas sensing.
Vanadium dioxide; Phase transition, Refractive index modulation; NIR; Plasmon tenability; Smart Windows; Nano-plasmonics; Ultrafast transition
M. Maaza. Optoelectronic Ultrafast Tunability in VO2 Based Mott/Peierls Nanostructures. Ann Nanosci Nanotechnol. 2017;1(1):1002.