Active thermal-electronic devices based on heat-sensitive metal-insulator-transition resistor elements

From multilayers to V1-xWxO2±δ films elaborated by magnetron sputtering for decreasing thermochromic transition temperature

“…Materials with tunable Metal-Insulator Transition (MIT) are of great interest in various applications such as thermals sensors, electronic switches, adaptive infrared camouflage, smart windows, etc [1,2,3]. Among several MIT materials, vanadium dioxide (VO2) shows a first order reversible transition from a monoclinic structure (M1, P21/c) to a rutile structure (R, P42/mnm) at around 68 °C [4] which is closer to room temperature than any other thermochromic materials.…”

Neuromorphic thermal-electric circuits based on phase-change VO2 thin-film memristor elements

“…As it was already mentioned, the thermo-electric logic circuits (TELCs) can process both electrical and thermal forms of energy as information signals. 1,4 This concept can be extended further, beyond logic switching operation of the VO 2 resistor devices, for example, to mimic the biological neuron synapse structure and operation, as shown in Fig. 2.…”

“…Even though the properties of such systems are simulated numerically by us and the other groups, it is hardly necessary go through those results in this paper, which is a presentation of the novel ideas and functionalities of the prototype circuits to be utilized in neuromorphic applications. [3][4][5]8 Indeed, in Fig. 3(a), there is a circuit having two VO 2 resistor devices with thermal signal connection presented, analogous to the configuration in Fig.…”

“…The above listed features are more or less valid for the phonsistor based TELC system too. It is basically a digital and parallel logic structure, 7 but the phonsistor can also be considered as an analog device (see the previous paragraph, as well as the measured thyristor-like input and output characteristics 1,4 ). However, two or more subthreshold excitations within the thermal time constant on the same input of a TELC gate may result in switch on, i.e., sequential AND operation, similarly to the effect of subthreshold stimuli on neuron within recovery time.…”

“…When the VO 2 devices, most often only simple resistor elements, are connected to appropriate pull-up resistors and are biased, this functionality of the material can be measured as current gain β and transfer admittance g m , representing exactly the corresponding properties of conventional active transistor elements. 4 When this kind of simple resistor networks are integrated together, perhaps with the present CMOS technology, they offer a totally new technological platform for micro-and nanoelectronics integration, for example, in More-Than-Moore concept devices.…”