Formation of Schottky-type metal/SrTiO3 junctions and their resistive properties

Stöcker, Hartmut; Zschornak, Matthias; Seibt, Juliane; Hanzig, Florian; Wintz, Susi; Abendroth, Barbara; Kortus, Jens; Meyer, Dirk C.

doi:10.1007/s00339-010-5848-0

Cited by 27 publications

(13 citation statements)

References 31 publications

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“…Particularly, forming reliable, low‐resistance ohmic contacts are of critical importance to the advancement of oxide electronics. Majority of metals form Schottky barriers when deposited on oxide surfaces . Among functional oxides, Ti‐based oxides including titanium dioxide (TiO 2 ) and strontium titanium oxide (SrTiO 3 /STO) are widely investigated.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO₃

Wang

et al. 2016

Adv Materials Inter

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high-performance optoelectronics such as light emitting diodes and laser diodes. [1][2][3] Such transparent contacts allow high charge injection and improve thermal stability, which is critical for reliable device operation. Electrodes with different metals and their combinations have been extensively explored, [4][5][6][7][8] which motivated researchers to examine the microscopic structures of the interfaces between semiconductors and metals.Functional oxides have a broad range of technological applications due to their unique properties such as ferroelectricity, piezoelectricity, high-T C superconductivity, colossal magnetoresistance, and so on. Particularly, forming reliable, low-resistance ohmic contacts are of critical importance to the advancement of oxide electronics. Majority of metals form Schottky barriers when deposited on oxide surfaces. [9][10][11] Among functional oxides, Ti-based oxides including titanium dioxide (TiO 2 ) and strontium titanium oxide (SrTiO 3 /STO) are widely investigated. STO is well known not only as popular substrate for film growth, but also for many interesting properties, such as superconductivity, [12] blue-light emission, [13][14][15] insulator-metal transition, [16] and photocatalytic properties. [17] Recently, STO has also been explored for resistive switching memory [18] and optoelectronic applications. [19][20][21] Ti is one of the earth-abundant elements, and it is frequently used to form contacts with oxides. Although the importance of metal/oxide interfaces has been well recognized, [22][23][24] there have been few works devoted to understanding the microscopic phenomena at such buried interfaces.In this work, we investigated the Ti/STO interfaces as a prototypical system using a series of complimentary imaging tools including high-resolution high-angle annular dark field (HAADF) and low-angle annular dark field (LAADF) scanning transmission electron microscopy (STEM), electron energy loss spectrum (EELS), and secondary ion mass spectrometry (SIMS). We observed substantial oxygen interdiffusion at the metal/ oxide interface, which is accompanied by the gradual evolution of the Ti valence from 4 + , 3 + to 0. Importantly, we discovered atomic-thin layer of cubic perovskite Ti 2 O 3 (Ti 3+ ) and anatase TiO 2 (Ti 4+ ) at the interfaces prepared at room temperature and 200 °C, respectively. Overall, our in-depth atomic-scale characterizations of the Ti/STO interfaces provide valuable structural and chemical information for such heterostructures, which could be generalized to the investigation of other interface systems.Metal/oxide interfaces are ubiquitous in a wide range of applications such as electronics, photovoltaics, memories, catalysis, and sensors. However, there have been few investigations dedicated to the nanoscale structural and chemical characteristics of these buried interfaces. In this work, the metal/oxide interface between Ti and SrTiO 3 (STO) is examined as a prototypical system using high-resolution scanning transmission electron microscopy and electr...

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Section: Introductionmentioning

confidence: 99%

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO₃

Wang

et al. 2016

Adv Materials Inter

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“…The ability to form reliable, low‐resistance Ohmic contacts is of critical importance to the ongoing development of oxide electronics. The vast majority of metals form Schottky barriers when deposited on oxide surfaces 1–3. Ohmic contacts rarely occur, and little is known at an atomistic level about what leads to a good Ohmic contact on a wide‐gap oxide.…”

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Ultralow Contact Resistance at an Epitaxial Metal/Oxide Heterojunction Through Interstitial Site Doping

Chambers

Sushko

et al. 2013

Advanced Materials

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“…Previous transport investigations have shown that Au, Ag, Cu, and Pt form Schottky barriers on STO, whereas Al forms an Ohmic contact. [7][8][9][10][11] It is also known that redox chemistry occurs at the Al/STO(001) interface at room temperature. 6 One common denominator in these previous studies is that structurally coherent bonding between the terminal atomic layer in the STO and the initial metal layer does not occur at the interface due to lattice mismatch.…”

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Epitaxial Cr on n-SrTiO3(001)—An ideal Ohmic contact

Capan

Sun

Bowden

et al. 2012

Applied Physics Letters

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Formation of Schottky-type metal/SrTiO3 junctions and their resistive properties

Cited by 27 publications

References 31 publications

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO₃

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO₃

Ultralow Contact Resistance at an Epitaxial Metal/Oxide Heterojunction Through Interstitial Site Doping

Epitaxial Cr on n-SrTiO3(001)—An ideal Ohmic contact

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Formation of Schottky-type metal/SrTiO3 junctions and their resistive properties

Cited by 27 publications

References 31 publications

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO3

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO3

Ultralow Contact Resistance at an Epitaxial Metal/Oxide Heterojunction Through Interstitial Site Doping

Epitaxial Cr on n-SrTiO3(001)—An ideal Ohmic contact

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Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO₃

Nanoscale Chemical and Valence Evolution at the Metal/Oxide Interface: A Case Study of Ti/SrTiO₃