@article{f1d57926899849c6a35228af34d31d5d,
title = "Shear-Induced Changes of Electronic Properties in Gallium Nitride",
abstract = "We show that sliding on the surface of GaN can permanently change the surface band structure, resulting in an increased degree of band bending by more than 0.5 eV. We hypothesize that shear and contact stresses introduce vacancies that cause a spatially variant band bending. Band bending is observed by shifts and broadening of core-level binding energies toward lower values in X-ray photoelectron spectroscopy. The extent of band bending is controlled by humidity, number of sliding cycles and applied load, presenting opportunities for scalable tuning of the degree of band bending on a GaN surface. Scanning transmission electron microscopy revealed that the epitaxy of GaN was preserved up to the surface with regions of defects near the surface. The hypothesized mechanism of band bending is shear-induced defect generation, which has been shown to affect the surface states. The ability to introduce band bending at the GaN surface is promising for applications in photovoltaics, photocatalysis, gas sensing, and photoelectrochemical processes.",
keywords = "band bending, gallium nitride, mechanochemistry, tribochemistry, tribodoping",
author = "Guosong Zeng and Xiaofang Yang and Tan, {Chee Keong} and Marvel, {Christopher J.} and Koel, {Bruce E.} and Nelson Tansu and Krick, {Brandon A.}",
note = "Funding Information: *E-mail: bakrick@lehigh.edu. ORCID Bruce E. Koel: 0000-0002-0032-4991 Brandon A. Krick: 0000-0003-3191-5433 Author Contributions G.Z., B.A.K., and N.T. contributed to the initial concept development, discussions, experimental design, analysis of the results, and writing of the manuscript. X.Y. and B.E.K. contributed to XPS analysis of the samples and helped in writing of the manuscript, and C.J.M. contributed to the TEM measurements of the samples. C.-K.T. sample preparations, initial concept development, and initial discussion of the project. All the authors contributed to technical discussions of the band bending analysis for the manuscript. B.A.K. and N.T. supervised the studies performed in the manuscript. Funding The support of the US National Science Foundation [CMMI 1538125] (G.Z. and B.A.K.), Lehigh University Doctoral Fellowship (G.Z.), and The E. Elmer Klaus Fellowship (G.Z.) is also appreciated. The sample preparation was supported by the US National Science Foundation [ECCS 1408051 and DMR 1505122] (N.T.) and the Daniel E. {\textquoteright}39 and Patricia M. Smith Endowed Chair Professorship Fund (N.T.). Notes The authors declare no competing financial interest. All data needed to evaluate the conclusions in the paper are present in the paper and/or in the Supporting Information. Additional data related to this paper may be requested from the authors. Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",
year = "2018",
month = aug,
day = "29",
doi = "10.1021/acsami.8b02271",
language = "English (US)",
volume = "10",
pages = "29048--29057",
journal = "ACS Applied Materials and Interfaces",
issn = "1944-8244",
publisher = "American Chemical Society",
number = "34",
}