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

Abstract

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.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [2];  [3];  [4];  [5];  [2];  [1];  [1]
  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
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1378042
Report Number(s):
PNNL-SA-127447
Journal ID: ISSN 1944-8244; KC0203020
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Applied Materials and Interfaces; Journal Volume: 9; Journal Issue: 31
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Transparent Conducting Oxides; Oxide Heterojunctions; Electronic Structure; Band Offset; Photocatalysis; NiO; Perovskite Oxide

Citation Formats

Zhang, Kelvin H. L., Wu, Rui, Tang, Fengzai, Li, Weiwei, Oropeza, Freddy E., Qiao, Liang, Lazarov, Vlado K., Du, Yingge, Payne, David J., MacManus-Driscoll, Judith L., and Blamire, Mark G.. Electronic Structure and Band Alignment at the NiO and SrTiO 3 p–n Heterojunctions. United States: N. p., 2017. Web. doi:10.1021/acsami.7b06025.
Zhang, Kelvin H. L., Wu, Rui, Tang, Fengzai, Li, Weiwei, Oropeza, Freddy E., Qiao, Liang, Lazarov, Vlado K., Du, Yingge, Payne, David J., MacManus-Driscoll, Judith L., & Blamire, Mark G.. Electronic Structure and Band Alignment at the NiO and SrTiO 3 p–n Heterojunctions. United States. doi:10.1021/acsami.7b06025.
Zhang, Kelvin H. L., Wu, Rui, Tang, Fengzai, Li, Weiwei, Oropeza, Freddy E., Qiao, Liang, Lazarov, Vlado K., Du, Yingge, Payne, David J., MacManus-Driscoll, Judith L., and Blamire, Mark G.. Tue . "Electronic Structure and Band Alignment at the NiO and SrTiO 3 p–n Heterojunctions". United States. doi:10.1021/acsami.7b06025.
@article{osti_1378042,
title = {Electronic Structure and Band Alignment at the NiO and SrTiO 3 p–n Heterojunctions},
author = {Zhang, Kelvin H. L. and Wu, Rui and Tang, Fengzai and Li, Weiwei and Oropeza, Freddy E. and Qiao, Liang and Lazarov, Vlado K. and Du, Yingge and Payne, David J. and MacManus-Driscoll, Judith L. and Blamire, Mark G.},
abstractNote = {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.},
doi = {10.1021/acsami.7b06025},
journal = {ACS Applied Materials and Interfaces},
number = 31,
volume = 9,
place = {United States},
year = {Tue Jul 25 00:00:00 EDT 2017},
month = {Tue Jul 25 00:00:00 EDT 2017}
}