Guanlin Xie

Strain-assisted tunneling current through TbMnO3∕Nb-1 wt %-doped SrTiO3 p–n junctions

Simple oxide heterostructures have been fabricated by growing multiferroic TbMnO3 thin film on Nb-1 wt %-doped SrTiO3 substrate. In addition to the beneficial rectifying characteristics in a temperature range from 350 to 30 K, the intriguing observation is that at constant reverse bias the current increases with decreasing temperature below 275 K. By analyzing the band diagram, the anomalous increasing current with decreasing temperature was ascribed to the strain-assisted tunneling current through TbMnO3∕Nb-doped p–n junctions.

Investigation of the resistance switching in Au/SrTiO3:Nb heterojunctions

The electric properties of as-prepared and annealed Au/SrTiO3:Nb heterojunctions are comparatively investigated. The former junction has hysteretic current-voltage and apparent capacitance-voltage characteristics, showing significant resistance switching effects. The latter behaves like a conventional semiconductor Schottky contact with negligible resistance switching phenomena. Based on the equivalent circuit analysis, we demonstrated that the hysteresis of the measured apparent capacitance-voltage relation of the as-prepared junction is caused by the leakage resistance. Its real junction capacitance is not hysteretic and independent on the resistance states, following the ideal Schottky model. Our results suggest that during the resistance switching, the Schottky barrier profile is kept unchanged, and the conductive filaments play a vital role.

Fabrication and transport properties of ZnO∕Nb-1wt%-doped SrTiO3 epitaxial heterojunctions

(110) ZnO/(001) Nb-1 wt %-doped SrTiO3 n-n type heteroepitaxial junctions were fabricated using the pulse laser deposition method. A diodelike current behavior was observed. Different from conventional p-n junctions or Schottky diodes, the diffusion voltage was found to increase with temperature. At all temperatures, the forward current was perfectly fitted on the thermionic emission model. The band bending at the interface can qualitatively explain our results, and the extracted high ideality factor at low temperatures, as well as large saturation currents, is ascribed to the deep-level-assisted tunneling current through the junction

Mechanical writing of n-type conductive layers on the SrTiO3 surface in nanoscale

The fabrication and control of the conductive surface and interface on insulating SrTiO3 bulk provide a pathway for oxide electronics. The controllable manipulation of local doping concentration in semiconductors is an important step for nano-electronics. Here we show that conductive patterns can be written on bare SrTiO3 surface by controllable doping in nanoscale using the mechanical interactions of atomic force microscopy tip without applying external electric field. The conductivity of the layer is n-type, oxygen sensitive, and can be effectively tuned by the gate voltage. Hence, our findings have potential applications in oxide nano-circuits and oxygen sensors.