Probing Relaxation Dynamics and Stepped Domain Switching in Boron‐Alloyed VO₂

Abstract

The characteristic metal–insulator phase transition (MIT) in vanadium dioxide results in nonlinear electrical transport behavior, allowing VO2 devices to imitate the complex functions of neurological behavior. Chemical doping is an established method for varying the properties of the MIT, and interstitial dopant boron has been shown to generate a unique dynamic relaxation effect in individual B‐VO2 particles. This paper describes the first demonstration of an electrically stimulated B‐VO2 proto‐device which manifests a time‐dependent critical transformation temperature and switching voltage derived from the coupling of dopant diffusion dynamics and the metal–insulator transition of VO2. During quasi‐steady current‐driven transitions, the electrical responses of B‐VO2 proto‐devices show a step‐by‐step progression through the phase transformation, evidencing domain transformations within individual particles. The dynamic relaxation effect is shown to increase the critical switching voltage by up to 41% (ΔVcrit = 0.13 V) and also to increase the resistivity of the M1 phase of B‐VO2 by 14%, imbuing a memristive response derived from intrinsic material properties. These observations demonstrate the dynamic relaxation effect in B‐VO2 proto‐devices whose electrical transport responses can be adjusted by electronic phase transitions triggered by temperature but also by time as a result of intrinsic dynamics of interstitial dopants.

Interplay between boron doping and epitaxial relationships in VO2 films grown by laser ablation

“…Several parameters are known to influence T IMT , such as the synthesis technique and conditions (impacting among other things the vanadium valence state and the amount of intrinsic point defects), the existence of strains in the material (induced by epitaxy or doping) and the eventual addition of a dopant element. In the case of boron doping, it was recently suggested that thermal and time histories might play a crucial role as interstitial boron atoms could diffuse in the VO 2 lattice, leading to a gradual modification of both T IMT and resistivity [18] (and references therein).…”

Harnessing the Metal–Insulator Transition of VO2 in Neuromorphic Computing

“…[74,87] Inclusion of boron also creates pinning sites that cause the phase transition to occur in a step-like manner over a range of applied current or voltage values. [212] While information on the thermally driven MIT for doped VO 2 is extensive, the electrically driven MIT of doped VO 2 thin films remain relatively underexplored.…”

Multiphysical Field Modulated VO2 Device for Information Encryption

“…As a typical correlated material, VO 2 crystal undergoes significant insulator-to-metal transition (IMT) behavior near 340K, accompanied by great changes in conductivity, infrared transmittance, and other properties. [20][21][22] This unique IMT behavior of VO 2 compound makes it broad applications in the fields of ultrafast photoelectric switching, [23] neuron computing, [24,25] resistive storage, [26] microbrakes, [27] etc. Importantly, the insulator-metal phase transition of VO 2 can be effectively triggered or modulated by various external stimuli such as elemental doping, temperature, electric field, magnetic field, light, and stress.…”