Phase Transition Of Vanadium Dioxide Research Articles

Thermally Tuning Infrared Light Scattering Using Planar Layered Thin Films and Space Gradient Metasurface

We experimentally demonstrate a tunable planar layered thin film (PLTF) structure operating at the short-wavelength infrared spectrum by employing the phase transition of vanadium dioxide through thermal stimulus. We obtain 400-nm spectral wavelength shift of scattering resonances by heating up or cooling down the structure. This temperature change leads to a contrast in the scattering intensities so that the contrast of transmission at Fabry–Perot resonance wavelength of 1.75 μm is obtained by the numerical simulations and verified by the measurements. We add a metasurface layer on the tunable PLTF structure, and we theoretically investigate and numerically demonstrate the scattering effects of this modified design. In this case, the contrast of transmission is enhanced compared to the only PLTF design due to Mie-type scattering. We also indicate that the normally incoming infrared light passes through the proposed design with a bending angle at room temperature whereas the intensity of the bending light is not appreciable at high temperature. Thus, we have achieved the so-called thermally adjustable infrared light bending/steering. The dynamic devices based on these kinds of pure planar layered and metasurface incorporated structures can be employed in numerous active photonic applications in the infrared spectrum.

Fabrication, photoresponse and temperature dependence of n-VO2/n-MoSe2 heterojunction diode

Abstract Transition metal dichalcogenides are being interest in study for their optoelectronic device applications. This is an upsurge in research efforts after realizing monolayer device structures. This article presents the use of vanadium dioxide phase transition from monoclinic to rutile for obtaining heterojunction to Schottky diode characteristic transition. I V characteristics of VO2/MoSe2 heterojunction diode has studied in the temperature range 303 K–343 K. The results reveal the rectifying nature of the junction at 303 K. As temperature increases, rectification decreases and swings towards Schottky junction characteristics due to MIT behaviour of VO2 thin film. The heterojunction has also investigated in dark condition and under the photo intensity ranging from 10 to 60 mW/cm2. The pronounced rise in forward and reverse current was observed when the junction was exposed under the light. The typical diode parameters such as ideality factor, saturation current, Richardson constant, and responsivity (R), sensitivity (S) and detectivity (D) are determined for the quantitative analysis of VO2/MoSe2 heterojunction. I V characteristics of the diode resemble to photodiode I V characteristics.

Temperature-Controlled Asymmetric Transmission of Electromagnetic Waves

Chiral materials can exhibit different levels of transmission for opposite propagation directions of the same electromagnetic wave. Here we demonstrate thermal switching of asymmetric transmission of linearly polarized terahertz waves. The effect is observed in a terahertz metamaterial containing 3D-chiral metallic inclusions and achiral vanadium dioxide inclusions. The chiral structure exhibits pronounced asymmetric transmission at room temperature when vanadium dioxide is in its insulator phase. As the metamaterial is heated, the insulator-to-metal phase transition of vanadium dioxide effectively renders the structure achiral and the transmission asymmetry vanishes. We demonstrate the effect numerically and experimentally, describe it analytically and explain the underlying physical mechanism based on simulated surface current distributions. Potential applications include directionally asymmetric active devices as well as intensity and polarization modulators for electromagnetic waves.

An intelligent light-driven thermoelectric conversion system through the thermosensitive phase transition of vanadium dioxide

A new intelligent light-driven thermoelectric conversion system was designed, which contained PS/Fe2O3-GNS, VO2 film and a thermoelectric module. This system can realize light-thermal-electric conversion and obtain a stable current under sunlight.

Broad band antireflection in terahertz band based on vanadium dioxide phase transition

Broad band antireflection in terahertz band based on vanadium dioxide phase transition

Optical measurement of phase transition induced by friction

Abstract Optical effects are measured during the phase transition of vanadium dioxide (VO 2 ) exposed to friction, thereby opening new possibilities for friction measurements and detection. Exposure to periodic cycles of kinetic friction yield measurable, repeatable and reversible changes in optical properties of the films. Changes in reflectance are detected with thermal flux intensities as low as 1 mW/cm 2 . Characteristic response and recovery times are studied and modelled, as well as the effect of operating temperature, friction speed, pressure, friction coefficient and the thermal properties of the substrate.

Dynamically tunable perfect absorption based on the phase transition of vanadium dioxide with aluminum hole arrays

Integrating plasmonic nanostructures with functional materials can further control over the optical resonant responses. A perfect absorber (PA) consisting of aluminum (Al) ring array intercalated with vanadium dioxide (VO2) disk is presented. The resonance wavelength of absorption peak can be tuned over a wide range in the visible (Vis) and near-infrared (NIR) regimes. The absorption peak shifts from 770 nm to 1336 nm while VO2 undergoes a structural transition from metallic phase (m-VO2) to insulator phase (i-VO2), resulting in a relative 73.5% wavelength shift. In addition, the absorption peak is strongly dependent on the height and radius of the ring disk as well as the period of lattice. Our work also suggests that the designed VO2-based absorber has the potential to overcome the difficulty in performing dynamically tunable resonances and near-unity absorbance with wide angle of incidence as well as weak polarization dependence.

Vanadium Dioxide: The Multistimuli Responsive Material and Its Applications.

The reversible, ultrafast, and multistimuli responsive phase transition of vanadium dioxide (VO2 ) makes it an intriguing "smart" material. Its crystallographic transition from the monoclinic to tetragonal phases can be triggered by diverse stimuli including optical, thermal, electrical, electrochemical, mechanical, or magnetic perturbations. Consequently, the development of high-performance smart devices based on VO2 grows rapidly. This review systematically summarizes VO2 -based emerging technologies by classifying different stimuli (inputs) with their corresponding responses (outputs) including consideration of the mechanisms at play. The potential applications of such devices are vast and include switches, memories, photodetectors, actuators, smart windows, camouflages, passive radiators, resonators, sensors, field effect transistors, magnetic refrigeration, and oscillators. Finally, the challenges of integrating VO2 into smart devices are discussed and future developments in this area are considered.

Radiative Thermal Runaway Due to Negative-Differential Thermal Emission Across a Solid-Solid Phase Transition

Thermal runaway occurs when a rise in system temperature results in heat generation rates exceeding dissipation rates. Here we demonstrate that thermal runaway occurs in thermal radiative systems, given a sufficient level of negative differential thermal emission. By exploiting the insulator-to-metal phase transition of vanadium dioxide, we show that a small increase in heat generation (e.g., 10 nW/mm2) can result in a large change in surface temperature (e.g., ~35 K), as the thermal emitter switches from high emissivity to low emissivity. While thermal runaway is typically associated with catastrophic failure mechanisms, detailed understanding and control of this phenomenon may give rise to new opportunities in infrared sensing, camouflage, and rectification.

A Photonic Switch Based on a Hybrid Combination of Metallic Nanoholes and Phase-change Vanadium Dioxide

A photonic switch is an integral part of optical telecommunication systems. A plasmonic bandpass filter integrated with materials exhibiting phase transition can be used as a thermally reconfigurable optical switch. This paper presents the design and demonstration of a broadband photonic switch based on an aluminium nanohole array on quartz utilising the semiconductor-to-metal phase transition of vanadium dioxide. The fabricated switch shows an operating range over 650 nm around the optical communication C, L, and U band with maximum 20%, 23% and 26% transmission difference in switching in the C band, L band, and U band, respectively. The extinction ratio is around 5 dB in the entire operation range. This architecture is a precursor for developing micron-size photonic switches and ultra-compact modulators for thin film photonics.

Limiting Optical Diodes Enabled by the Phase Transition of Vanadium Dioxide

A limiting optical diode is an asymmetric nonlinear device that is bidirectionally transparent at low power, but becomes opaque when illuminated by sufficiently intense light incident from a particular direction. We explore the use of a phase-transition material, vanadium dioxide (VO2), as an active element of limiting optical diodes. The VO2 phase transition can be triggered by optical absorption, resulting in a change in refractive index orders of magnitude larger than what can be achieved with conventional nonlinearities. As a result, a limiting optical diode based on incident-direction-dependent absorption in a VO2 layer can be very thin, and can function at low powers without field enhancement, resulting in broadband operation. We demonstrate a simple thin-film limiting optical diode comprising a transparent substrate, a VO2 film, and a semi-transparent metallic layer. For sufficiently high incident intensity, our proof-of-concept device realizes broadband asymmetric transmission across the near infrared, and is approximately ten times thinner than the free-space wavelength.

Electrically tunable mid-infrared antennas based on VO2

A large change in optical constants of phase-change vanadium dioxide enables active control over the transmission and reflection properties of structures incorporating VO2. In this paper, we demonstrate electrically tunable mid-infrared strip array antennas based on metal–insulator transition of vanadium dioxide. The antennas consist of an interdigitated metal strip array separated from a metallic ground plane by a film of vanadium dioxide. The interdigitated metal strips serve as both antennas and electrodes. As the insulator-to-metal phase transition of vanadium dioxide is induced with applied voltages, resonance of the strip antenna array redshifts with reduced absorbance before it is eventually switched off. A tuning magnitude of 30% in reflectivity is measured at 25.5 THz. Our measurements of sample temperature reveal that tuning mechanism of the antennas is primarily thermal in nature. The demonstrated electrical tuning of mid-infrared antennas could be used for reconfigurable bolometric sensing, camouflaging and modulation of infrared radiations.

Dynamically Switching the Polarization State of Light Based on the Phase Transition of Vanadium Dioxide

Manipulating the polarization state of light is important in numerous applications in photonics and electromagnetism. Among many possible approaches, plasmonic polarizers have attracted widespread attention, due to their flexibility in structural design and convenience in on-chip integration. The authors demonstrate a VO${}_{2}$-based composite plasmonic nanostructure that can dynamically modulate the polarization of reflected light, via the thermally induced insulator-metal transition of the oxide. The composite structure can also be applied to realize switchable infrared imaging.

Switching Channel Development Dynamics in Planar Structures on the Basis of Vanadium Dioxide

The results of the experimental studies and numerical simulation of the switching channel development dynamics in planar structures on the basis of vanadium dioxide are reported. The obtained data on the variation of the temperature in the channel with time and of the current arisen after the pulsed load, and on the times of transition from the high-resistance to the low-resistance state and back are analyzed in order to determine the switching mechanism and to predict the functional characteristics of the switchable vanadium- oxide structures as promising materials for the creation of relaxation generators that can serve as prototypes of neural oscillators. It is shown that the switching behavior is associated with the metal–semiconductor phase transition in vanadium dioxide, which is stimulated by the emission of Joule heat.

Dynamic Plasmonic Color Generation Based on Phase Transition of Vanadium Dioxide

AbstractPlasmonic color filtering and color printing have attracted considerable attention in recent years due to their supreme performance in display and imaging technologies. Although various color‐related devices are designed, so far very few studies have touched the topic of dynamic color generation. In this article, dynamic color generation is demonstrated by integrating plasmonic nanostructures with vanadium dioxide based on its tunable optical properties through insulator–metal transition. Periodic arrays of silver nanodisks on a vanadium dioxide film are fabricated to realize different colors, relying on the excitation of localized and propagating surface plasmons, and Wood's anomaly. By tuning spatial periodicity of the arrays and diameter of the silver nanodisks, various colors can be achieved across the entire visible spectrum. Further, using insulator–metal transition of vanadium dioxide, the colors can be actively tuned by varying temperature. The approach of dynamic color generation based on the phase transition of vanadium dioxide can easily realize diverse color patterns, which makes it beneficial for display and imaging technology with distinct advantages of multifunctionality, flexibility, and high efficiency.

Thermally controlled femtosecond pulse shaping using metasurface based optical filters

AbstractShaping of the temporal distribution of the ultrashort pulses, compensation of pulse deformations due to phase shift in transmission and amplification are of interest in various optical applications. To address these problems, in this study, we have demonstrated an ultra-thin reconfigurable localized surface plasmon (LSP) band-stop optical filter driven by insulator-metal phase transition of vanadium dioxide. A Joule heating mechanism is proposed to control the thermal phase transition of the material. The resulting permittivity variation of vanadium dioxide tailors spectral response of the transmitted pulse from the stack. Depending on how the pulse’s spectrum is located with respect to the resonance of the band-stop filter, the thin film stack can dynamically compress/expand the output pulse span up to 20% or shift its phase up to 360°. Multi-stacked filters have shown the ability to dynamically compensate input carrier frequency shifts and pulse span variations besides their higher span expansion rates.

Динамика развития канала переключения в планарных структурах на основе диоксида ванадия

AbstractThe results of the experimental studies and numerical simulation of the switching channel development dynamics in planar structures on the basis of vanadium dioxide are reported. The obtained data on the variation of the temperature in the channel with time and of the current arisen after the pulsed load, and on the times of transition from the high-resistance to the low-resistance state and back are analyzed in order to determine the switching mechanism and to predict the functional characteristics of the switchable vanadium- oxide structures as promising materials for the creation of relaxation generators that can serve as prototypes of neural oscillators. It is shown that the switching behavior is associated with the metal–semiconductor phase transition in vanadium dioxide, which is stimulated by the emission of Joule heat.

A Lithography-Free and Field-Programmable Photonic Metacanvas.

The unique correspondence between mathematical operators and photonic elements in wave optics enables quantitative analysis of light manipulation with individual optical devices. Phase-transition materials are able to provide real-time reconfigurability of these devices, which would create new optical functionalities via (re)compilation of photonic operators, as those achieved in other fields such as field-programmable gate arrays (FPGA). Here, by exploiting the hysteretic phase transition of vanadium dioxide, an all-solid, rewritable metacanvas on which nearly arbitrary photonic devices can be rapidly and repeatedly written and erased is presented. The writing is performed with a low-power laser and the entire process stays below 90 °C. Using the metacanvas, dynamic manipulation of optical waves is demonstrated for light propagation, polarization, and reconstruction. The metacanvas supports physical (re)compilation of photonic operators akin to that of FPGA, opening up possibilities where photonic elements can be field programmed to deliver complex, system-level functionalities.

Broadband modulation of terahertz waves through electrically driven hybrid bowtie antenna-VO2 devices

Broadband modulation of terahertz (THz) light is experimentally realized through the electrically driven metal-insulator phase transition of vanadium dioxide (VO2) in hybrid metal antenna-VO2 devices. The devices consist of VO2 active layers and bowtie antenna arrays, such that the electrically driven phase transition can be realized by applying an external voltage between adjacent metal wires extended to a large area array. The modulation depth of the terahertz light can be initially enhanced by the metal wires on top of VO2 and then improved through the addition of specific bowties in between the wires. As a result, a terahertz wave with a large beam size (~10 mm) can be modulated within the measurable spectral range (0.3–2.5 THz) with a frequency independent modulation depth as high as 0.9, and the minimum amplitude transmission down to 0.06. Moreover, the electrical switch on/off phase transition depends very much on the size of the VO2 area, indicating that smaller VO2 regions lead to higher modulation speeds and lower phase transition voltages. With the capabilities in actively tuning the beam size, modulation depth, modulation bandwidth as well as the modulation speed of THz waves, our study paves the way in implementing multifunctional components for terahertz applications.

Stage-by-stage modeling of the mechanism of semiconductor–metal phase transition in vanadium dioxide

The algorithm of stage-by-stage qualitative modeling of the mechanism of a semiconductor–metal phase transition in vanadium dioxide has been proposed. The basis for the model is a statement that the transition is complex in character and consists of the anhysteretic, purely electronic Моtt transition occurring over a wide temperature range, and the temperature-abrupt structural Peierls transition having a thermal hysteresis. The initial stage of the model is based on the solution of a quantum-mechanical problem of an electronic spectrum of a linear vanadium-ion's chain. The model is completed by consideration of correlation effects and a martensitic character of the structural transition through taking consecutively account of results obtained by X-ray, spectroscopic, impedansmetric and magnetic resonance methods.