Elastic modulus and hardness of cubic GaN grown by molecular beam epitaxy obtained by nanoindentation

• Published in: Thin solid films Vol. 699; p. 137915
• Main Authors: García Hernández, S.A., Compeán García, V.D., López Luna, E., Vidal, M.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2020
• Subjects: Berkovich identation; Cubic gallium nitride; Mechanical properties; Plasma-assisted molecular beam epitaxy; Thin films; Young's modulus; Thin films; Mechanical properties; Young's modulus; Plasma-assisted molecular beam epitaxy; Berkovich identation; Cubic gallium nitride
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2020.137915

•Cubic phase gallium nitride (c-GaN) was grown by molecular beam epitaxy.•Nanoindentation was used to evaluate the mechanical properties of c-GaN.•Pop-in events are observed at different depths in load-displacement curves.•Hardness and Young's modulus of c-GaN are 22±1 GPa and 293±12.
The mechanical properties of gallium nitride thin films in the cubic phase (c-GaN) measured by Berkovich nanoindentation are reported here. The c-GaN thin films were grown on MgO (100) substrates by plasma-assisted molecular beam epitaxy. The X-ray diffraction results show that GaN thin films correspond to more than 99% cubic phase in all cases. Plastic transitions called pop-in events are observed during loading in some load-displacement curves at different depths. We believe that pop-in event is present when the tip interacts with defects encountered at different depths. The mean values of the hardness and Young's modulus of cubic GaN are 22 ± 1 GPa, and 293 ± 12, respectively.