Electronic Structure and Band Alignment at the NiO and SrTiO ₃ p–n Heterojunctions

Journal Article · Tue Jul 25 04:00:00 EDT 2017 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/acsami.7b06025· OSTI ID:1378042

Zhang, Kelvin H. L. ^[1]; Wu, Rui ^[1]; Tang, Fengzai ^[1]; Li, Weiwei ^[1]; Oropeza, Freddy E. ^[2]; Qiao, Liang ^[3]; Lazarov, Vlado K. ^[4]; Du, Yingge ^[5]; Payne, David J. ^[2]; MacManus-Driscoll, Judith L. ^[1]; Blamire, Mark G. ^[1]

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1. Department of Materials Science &, Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K.
2. Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
3. School of Materials, The University of Manchester, Manchester M13 9PL, U.K.
4. Department of Physics, University of York, Heslington, York YO10 5DD, U.K.
5. Physical Sciences Division, Physical &, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States

Understanding the energetics at the interface including the alignment of valence and conduction bands, built-in potentials, and ionic and electronic reconstructions, is an important challenge in designing oxide interfaces that have controllable multi-functionalities for novel (opto-)electronic devices. In this work, we report detailed investigations on the hetero-interface of wide bandgap p-type NiO and n-type SrTiO3 (STO). We show that despite a large lattice mismatch (~7%) and dissimilar crystal structure, high-quality NiO and Li doped NiO (LNO) thin films can be epitaxially grown on STO(001) substrates through a domain matching epitaxy (DME) mechanism. X-ray photoelectron spectroscopy (XPS) studies indicate that NiO/STO heterojunctions form a type II “staggered” band alignment. In addition, a large built-in potential of up to 0.97 eV was observed at the interface of LNO and Nb doped STO (NbSTO). The LNO/NbSTO p-n heterojunctions exhibit a large rectification ratio of 2×103, but also a large ideality factor of 4.3. The NiO/STO p-n heterojunctions have important implication for applications in photocatalysis and photodetector as the interface provides favourable energetics for facile separation and transport of photogenerated electrons and holes.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1378042
• Report Number(s): PNNL-SA-127447; KC0203020
• Journal Information: ACS Applied Materials and Interfaces, Journal Name: ACS Applied Materials and Interfaces Journal Issue: 31 Vol. 9; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Band Offset
Electronic Structure
NiO
Oxide Heterojunctions
Perovskite Oxide
Photocatalysis
Transparent Conducting Oxides