External electric field manipulations on structural phase transition of vanadium dioxide nanoparticles and its application in field effect transistor

Despite the intensive study on the famous metal-insulator transition, many questions regarding the evolution of the structural phase transition (SPT) in vanadium dioxide (VO₂) remain unresolved. Here, the lattice vibrations and SPT of VO₂ nanoparticles on a SiO₂/Si(100) substrate with different applied voltage from 0 to 8 V have been investigated by Raman scattering spectra. It can be found that both the intensities of the A_g and B_g phonon modes decrease with increasing temperature. Moreover, the vibration modes disappear when heating up to the temperature of SPT (T_SPT). With the voltage increasing from 0 to 8 V, the T_SPT decreases from 68.3 to 64.3 °C for the heating process and from 66.3 to 58.8 °C for the cooling process, respectively. The fitting results reveal that the T_SPT was decreased by -0.48 and -0.87 °C/V in the heating and cooling processes, respectively. This is because the larger electric field could assist the shortening of the V-V distance and the change of carriers between electrons and the mixing of electrons and holes. Moreover, the T_SPT delay was increased by 0.4 °C/V with increasing the positive voltage because the electric field can pull the electrons and push the holes. The present results of the VO₂ three-terminal device show a potential realization of the VO₂-based field effect transistor.