Noncontact evaluation of the interface potential in VO2/Si heterojunctions across metal–insulator phase transition

This study conducted laser-induced terahertz emission spectroscopy on a VO2/Si heterojunction. Consequently, rapid estimation of the local interface potential was realized and the work function of VO2 was obtained as 5.17–5.25 eV with increasing temperature from 320 to 380 K. Moreover, an obvious terahertz emission variation was observed across the metal–insulator phase transition of VO2, and the doping conditions of the Si substrate largely influenced the terahertz emission. These results imply a strong relationship between the terahertz emission amplitude and the interface electric field, which supports the rapid performance of terahertz emission spectroscopy in estimating the work function of VO2.