Field-Effect Modulation of the Negative Temperature Coefficient Effect in SrTiO ₃ -Based Thermal Sensors

Negative temperature coefficient (NTC) oxide thermal sensors play a vital role in industry, healthcare, and daily life. Traditionally, tuning their thermosensitive behavior requires material modifications, which are often inconvenient. In this work, we present an approach to actively modulating the thermal response of NTC sensors by applying an electric field, enabling precise and reversible control without altering the material itself. The NTC sensors were fabricated using SrTiO3 crystals in a field-effect transistor architecture, which allows an electric field to be applied through the gate without interfering with the bias used for resistance reading. The application of a gate voltage from 8 to 12 V gradually reduces the overall resistance of the NTC sensors and enhances the temperature coefficient of resistance (TCR) from 5.94%·K–1 to 9.97%·K–1 at 140 K, an increase of 67%. Correspondingly, the linearity (R2) of the resistance–temperature fitting curve rises from 0.90 to 0.98. Under a relative uncertainty (ur) below 2%, the reliable operating temperature range is significantly extended from 182–350 to 144–350 K. The enhancement in the NTC performance is mainly attributed to the electric field modulation of the Coulomb impurity screening and thermally activated conduction mechanisms. This work provides a feasible strategy for modulating the thermal sensing behavior of NTC oxides via an electric field.