Properties of graphene deposited on GaN nanowires: influence of nanowire roughness, self-induced nanogating and defects

Jakub Kierdaszuk; Piotr Kaźmierczak; Justyna Grzonka; Aleksandra Krajewska; Aleksandra Przewłoka; Wawrzyniec Kaszub; Zbigniew R Zytkiewicz; Marta Sobanska; Maria Kamińska; Andrzej Wysmołek; Aneta Drabińska

doi:10.3762/bjnano.12.47

Properties of graphene deposited on GaN nanowires: influence of nanowire roughness, self-induced nanogating and defects

Beilstein J Nanotechnol. 2021 Jun 22:12:566-577. doi: 10.3762/bjnano.12.47. eCollection 2021.

Authors

Affiliations

¹ Faculty of Physics, University of Warsaw, Warsaw, Poland.
² University of Cadiz, Department of Material Science and Metallurgy Engineering and Inorganic Chemistry, Cadiz, Spain.
³ Łukasiewicz - Institute of Microelectronics and Photonics, Warsaw, Poland.
⁴ CENTERA Laboratories, Institute of High Pressure Physics PAS, Warsaw, Poland.
⁵ Institute of Optoelectronics, Military University of Technology, Warsaw, Poland.
⁶ Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland.

Abstract

We present detailed Raman studies of graphene deposited on gallium nitride nanowires with different variations in height. Our results indicate that different density and height of nanowires impact graphene properties such as roughness, strain, and carrier concentration as well as density and type of induced defects. Tracing the manifestation of those interactions is important for the application of novel heterostructures. A detailed analysis of Raman spectra of graphene deposited on different nanowire substrates shows that bigger differences in nanowires height increase graphene strain, while a higher number of nanowires in contact with graphene locally reduces the strain. Moreover, the value of graphene carrier concentration is found to be correlated with the density of nanowires in contact with graphene. The lowest concentration of defects is observed for graphene deposited on nanowires with the lowest density. The contact between graphene and densely arranged nanowires leads to a large density of vacancies. On the other hand, grain boundaries are the main type of defects in graphene on rarely distributed nanowires. Our results also show modification of graphene carrier concentration and strain by different types of defects present in graphene. Therefore, the nanowire substrate is promising not only for strain and carrier concentration engineering but also for defect engineering.

Keywords: Raman spectroscopy; carrier concentration; gallium nitride; graphene; nanowires; scattering on defects; strain.

Grants and funding

This work was partially supported by the Ministry of Science and Higher Education in 2015–2019 as a research grant “Diamond Grant” (n°. DI2014 015744). The GaN nanowires were grown within the Polish National Science Centre (grants n°. UMO-2016/21/N/ST3/03381 and 2016/23/B/ST7/03745). This work was supported by the Research Foundation Flanders (FWO) under grant n°. EOS 30467715. The data that support the findings of this study are available from the corresponding author upon reasonable request.