High temperature transport properties at metal/SrTiO3 interfaces

Kawada, Tatsuya; Iizawa, Naofumi; Tomida, M; Kaimai, Atsushi; Kawamura, Ken; Nigara, Yutaka; Mizusaki, Junichiro

doi:10.1016/s0955-2219(98)00297-0

Cited by 21 publications

(18 citation statements)

References 16 publications

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“…When it was annealed in oxygen containing gases, the interface resistance increased, and a rectification behavior appeared. Similar results were obtained also in our previous studies on the Pt/STNO interface with higher Nb concentration (1 mol%) [9]. In that case, however, a significant leak current was observed in the reverse bias.…”

Section: Resultssupporting

confidence: 91%

“…Niobium segregation, Sr vacancy and/or Sr n+1 Ti n O 3n+1 phase formation, or Schottky barrier have been considered in the literatures as the reason of the high resistivity. The present authors have reported that the interface between platinum and 1 mol% Nb doped SrTiO 3 exhibits Schottky barrier type rectification behavior even at high temperatures as 600 • C [9]. The barrier height reversibly varied with the partial pressure of ambient oxygen.…”

Section: Introductionmentioning

confidence: 63%

“…E-mail: kawada@tagen.tohoku.ac.jp clarified enough. For donor doped SrTiO 3 , the grain boundary or the surface are known to have much higher resistance than the bulk [1][2][3][4][5][6][7][8][9]. Niobium segregation, Sr vacancy and/or Sr n+1 Ti n O 3n+1 phase formation, or Schottky barrier have been considered in the literatures as the reason of the high resistivity.…”

Section: Introductionmentioning

confidence: 99%

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High Temperature Schottky Barrier on n-Type SrTiO3 and Its Sensitivity to Ambient Gases

et al. 2004

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Metal or oxide electrodes (Pt, Au, Ag, (La,Sr)CoO 3 ) were deposited on single crystals of 0.02 mol% Nb doped SrTiO 3 by pulsed laser deposition. Current-voltage and capacitance-voltage responses were measured using three-terminal electrode configuration. Under high oxygen partial pressures, clear rectification behaviors were observed. Diffusion model well explained the current vs. voltage relationship with ideality factors close to unity. The barrier height varied reversibly with oxygen partial pressure, and was almost independent of the electrode materials, which suggested that the Fermi level at the interface was pinned by the surface states. The origin of the surface states was discussed in terms of oxygen adsorption or oxidative formation of metal vacancies around the surface. Chemical interaction between the surface and oxygen and resulting cation rearrangement was concluded to play an important role from the long stabilization time on oxygen partial pressure change. The water vapor pressure dependence of the barrier height was also explained by competitive adsorption of oxygen and water.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

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High Temperature Schottky Barrier on n-Type SrTiO3 and Its Sensitivity to Ambient Gases

et al. 2004

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“…[11][12][13] These experimental results demonstrate the possibility of a fabrication of the photoelectronic devices using SrTiO 3 for high temperature uses. However, it has not been examined so far based on a theoretical approach.…”

mentioning

confidence: 57%

“…[17][18][19] We consider that the barrier formation mechanism is interpreted by the Bardeen limit at high temperatures 17 because the surface defects probably determine the interface states. Thus, the value of the barrier height measured in the previous studies 11,12 is used in this study. In the interface-electron-transport analysis, calculation is made on the population of electrons passing through the barrier.…”

mentioning

confidence: 99%

Design Concept for the High Temperature Photoelectronic Devices Using SrTiO[sub 3]

Horikiri

Sato

Yashiro

et al. 2009

J. Electrochem. Soc.

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A quantum electronic discussion was made on the metal/SrTiO 3 heterostructure to obtain the design concept for the high temperature photoelectronic devices using SrTiO 3 . The current density ratios were calculated from the simulated values for the tunneling and the thermionic emission components of the electron transports across the heterointerface. The ratios indicate the required dopant concentrations to achieve Ohmic and Schottky contacts. The Wentzel-Kramers-Brillouin approximation and the Gamow transmission coefficient were used in the calculation of the tunneling transmission coefficient. The calculated results indicate that the tunneling transport of electrons across the heterointerface is predominant in a heavy 10 mol % doped substrate, whereas the thermionic emission is predominant in a 1 or 0.1 mol % doped substrate. It agrees with experimental results on the current-voltage characteristics at the metal/Nb-doped SrTiO 3 single-crystal interfaces. The possibility of the high temperature photoelectronic devices using SrTiO 3 was shown both in theoretical and experimental approaches. Strontium titanate ͑SrTiO 3 ͒, a typical perovskite-type oxide semiconductor, is an interesting material that can be used in various applications such as dynamic random access memories, field-effecttype devices, and oxygen sensors. 1-6 It is well known that the ideal Schottky barrier is formed at the interface between metal electrodes and SrTiO 3 substrates. 7-10 Also, SrTiO 3 has a high chemical stability up to high temperatures over 1723 K because Ti 4+ ions are quite stable. These properties make SrTiO 3 a candidate material for the high temperature electronic devices.Recently, the nonlinear current-voltage characteristics and the photovoltaic effects of the Schottky interface on SrTiO 3 single crystals were observed even at high temperatures. 11-13 These experimental results demonstrate the possibility of a fabrication of the photoelectronic devices using SrTiO 3 for high temperature uses. However, it has not been examined so far based on a theoretical approach. The information on the carrier concentration, the barrier height, and the interface-electron-transport property is necessary in the process of device designing. Here, the carrier concentration is calculated from the defect chemical data 14-16 including dopant concentration, temperature, and oxygen partial pressure. The barrier height is the most important information at the heterointerface to determine the interface characteristics. It is difficult to calculate the value of the barrier height, except when the barrier formation mechanism is interpreted by the Schottky limit expected for an ultraclean interface. [17][18][19] We consider that the barrier formation mechanism is interpreted by the Bardeen limit at high temperatures 17 because the surface defects probably determine the interface states. Thus, the value of the barrier height measured in the previous studies 11,12 is used in this study. In the interface-electron-transport analysis, calculation is made on ...

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