Search

We performed capacitance-voltage analysis of 5-nm-thick LaAlO3/SrTiO3 heterostructure containing two-dimensional-electron-gas (2DEG) at the interface. The complex impedance of the heterostructure was measured as a function of frequency for a wide range of gate biases. The impedance spectra showed a different behavior above and below an applied voltage of -1.8 V. The capacitance determined from the impedance was approximately 1.2 nF above -1.8 V and was drastically reduced to ∼0.01 nF below this voltage, owing to depletion of 2DEG and the insulating SrTiO3 underneath it. This suggests that devices utilizing LaAlO3/SrTiO3 can facilitate switching operations in a very small voltage range. [ABSTRACT FROM AUTHOR]

The 2-dimensional electron gas (2DEG) at the LaAlO 3 /SrTiO 3 heterointerface was analyzed using frequency-dependent impedance spectroscopy. The electrical conduction of 2DEG significantly influences the high-frequency impedance and induces dielectric amplification at low frequency regimes. The impedance responses obtained from the LaAlO 3 /SrTiO 3 oxide was modeled using an equivalent circuit model. The frequency-dependent characterization used here does not necessitate the formation of ohmic contacts between the 2DEG layer and the adjacent electrodes. Through thermal bias-stress tests, the 2DEG conduction mechanism is proposed to partially originate from the oxygen vacancy-controlled defect concepts, indicating the controllability of 2DEG transport. [ABSTRACT FROM AUTHOR]