High Current Density SmTiO₃/SrTiO₃ Field-Effect Transistors

SmTiO3/SrTiO3 interfaces are of potential interest for electronic devices as they exhibit novel electronic phenomena such as metal–insulator transitions. However, good transistor performance from this material system requires advances in both device design and processing. Here, we demonstrate high current density SmTiO3/SrTiO3 transistors with good pinch-off by minimizing parasitic series resistances and improved field management using a narrow-channel constriction architecture. Constriction devices show improved pinch-off behavior and saturation current densities at room temperatures of 350 mA/mm along with transconductances of 200 mS/mm, which are the highest reported values for SrTiO3-based transistors. Temperature-dependent measurements reveal that these SmTiO3/SrTiO3 channels exhibit insulating behavior with the sheet resistance of the channel increasing with decreasing temperatures indicative of hopping transport of carriers in these devices.