PLASTIC PROPERTIES OF GaN AND Al2O3 CRYSTAL: FEM-SIMULATION OF NANOINDENTATION CONFIRMED BY HIGH-RESOLUTION MICROSCOPY
|Roman Nowak 4, Timo Manninen 4, Kari Heiskanen 4, Ari Lehto 4, Fusahito Yoshida 5,6, Mike Leszczynski 1, Jozef Lelatko 3, Henryk Morawiec , Krzysztof J. Kurzydlowski 2|
1. Polish Academy of Sciences, High Pressure Research Center (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland
The elastic properties of GaN were evaluated by Schwarz et al.,1 Yu et al.2 and finally confirmed by Nowak's et al.3 nanoindentation testing that agreed with the earlier first principles calculations.4-5 Our previous results run contrary a common expectation that GaN is particularly brittle material.3 Despite its high Young's modulus (295 GPa) and hardness (20 GPa), the nanoindentation stress-strain curves suggest elasto-plastic behaviour of the crystal. Consequently, the present research aims to resolve the surface deformation of GaN by using both microscopic observation of the surface features and structure, as well as finite element simulation of the nanoindentation deformation.
Presentation: invited oral at E-MRS Fall Meeting 2004, Symposium H, by Roman Nowak
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-08-10 13:48 Revised: 2009-06-08 12:55