Atomic-Scale Origin of Long-Term Stability and High Performance of p-GaN Nanowire Arrays for Photocatalytic Overall Pure Water Splitting

Md Golam Kibria; Ruimin Qiao; Wanli Yang; Idris Boukahil; Xianghua Kong; Faqrul Alam Chowdhury; Michel L Trudeau; Wei Ji; Hong Guo; F J Himpsel; Lionel Vayssieres; Zetian Mi

doi:10.1002/adma.201602274

Atomic-Scale Origin of Long-Term Stability and High Performance of p-GaN Nanowire Arrays for Photocatalytic Overall Pure Water Splitting

Adv Mater. 2016 Oct;28(38):8388-8397. doi: 10.1002/adma.201602274. Epub 2016 Jul 26.

Authors

Md Golam Kibria¹, Ruimin Qiao², Wanli Yang², Idris Boukahil³, Xianghua Kong^{4

5}, Faqrul Alam Chowdhury¹, Michel L Trudeau⁶, Wei Ji⁵, Hong Guo⁴, F J Himpsel⁷, Lionel Vayssieres⁸, Zetian Mi⁹

Affiliations

¹ Department of Electrical & Computer Engineering, McGill University, Montreal, QC, H3A0E9, Canada.
² Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
³ Department of Physics, University of Wisconsin Madison, Madison, WI, 53706, USA.
⁴ Department of Physics, McGill University, Montreal, QC, H3A2T8, Canada.
⁵ Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing, 100872, P. R. China.
⁶ Science des Matériaux, IREQ, Hydro-Québec, Varennes, QC, J3×1S1, Canada.
⁷ Department of Physics, University of Wisconsin Madison, Madison, WI, 53706, USA. fhimpsel@wisc.edu.
⁸ International Research Center for Renewable Energy, School of Energy & Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, P. R. China. lionelv@xjtu.edu.cn.
⁹ Department of Electrical & Computer Engineering, McGill University, Montreal, QC, H3A0E9, Canada. zetian.mi@mcgill.ca.

PMID: 27456856
DOI: 10.1002/adma.201602274

Abstract

The atomic-scale origin of the unusually high performance and long-term stability of wurtzite p-GaN oriented nanowire arrays is revealed. Nitrogen termination of both the polar (0001¯) top face and the nonpolar (101¯0) side faces of the nanowires is essential for long-term stability and high efficiency. Such a distinct atomic configuration ensures not only stability against (photo) oxidation in air and in water/electrolyte but, as importantly, also provides the necessary overall reverse crystal polarization needed for efficient hole extraction in p-GaN.

Keywords: N-terminated surfaces; X-ray spectroscopy; artificial photosynthesis; metal nitride; polarization dependence; wurtzite structure.