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 center dot 7Al(2)O(3) 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 10(6), threshold gate voltage of +1.1 V, subthreshold swing of approximately 0.3 V decade(-1), and effective mobility of 2 cm(2) V-1 s(-1). The field-modulated S-value of the SrTiO3-FET varied from -900 to -580 mu V 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. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3231873]