Field-modulated thermopower in SrTiO3-based field-effect transistors with amorphous 12CaO⋅7Al2O3 glass gate insulator

We report transistor characteristics and field-modulated thermopower (S) for single crystal SrTiO3-based field-effect transistors (FETs). We use 150-nm-thick amorphous 12CaO⋅7Al2O3 glass as the gate insulator of the SrTiO3-FET. The resulting SrTiO3-FET exhibits excellent transistor characteristics at room temperature: on-to-off current ratio greater than 106, threshold gate voltage of +1.1 V, subthreshold swing of approximately 0.3 V decade−1, and effective mobility of 2 cm2 V−1 s−1. The field-modulated S-value of the SrTiO3-FET varied from −900 to −580 μV K−1 with electric fields of up to 2 MV cm−1, demonstrating the effectiveness of the FET structure for the exploration of thermoelectric materials.