‘Pop-in’ phenomenon during nanoindentation in epitaxial GaN thin films on c-plane sapphire substrates

Navamathavan, R.; Moon, Yong-Tae; Kim, Gwang-Seok; Lee, Tae Geol; Hahn, Junhee; Park, Seong-Ju

doi:10.1016/j.matchemphys.2005.11.021

Cited by 36 publications

(9 citation statements)

References 15 publications

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“…5) exhibited no slip lines and the lack of any surface crack around the indentation marks. These results agree with the images presented by Navamathavan et al [34], while a number of papers [1,[7][8][9][10][11][12][13][14] claimed that slip lines appeared around the impression. The apparent discrepancies should be attributed to the difference of samples preparation techniques as well as to the conditions of the indentation examinations.…”

Section: Nanoindentation Testing In Gan Crystalsupporting

confidence: 92%

“…The mean pressure p m equal to 40 GPa is consistent with the reported value without any slip (shown in the inlet of Fig. 1 of Navamathavan et al [34]). This agreement indicates the high accuracy achieved with the best sample and the experimental conditions.…”

Section: Nanoindentation Testing In Gan Crystalsupporting

confidence: 91%

“…4b) indenter loaded up to P max equal to 5 mN. The discontinuities on the loading curves (pop-ins) were observed for all P-h curves, which agree with the previous similar results of indentation of thin film GaN on sapphire substrate [1,[7][8][9]15,34]. The Hertzian relationship is also illustrated in the figure, indicating that the deformation before the pop-in is completely elastic.…”

Section: Nanoindentation Testing In Gan Crystalsupporting

confidence: 89%

See 2 more Smart Citations

Elastic–plastic transition during nanoindentation in bulk GaN crystal

Fujikane

Leszczyński

Nagao

et al. 2008

Journal of Alloys and Compounds

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Section: Nanoindentation Testing In Gan Crystalsupporting

confidence: 92%

Section: Nanoindentation Testing In Gan Crystalsupporting

confidence: 91%

Section: Nanoindentation Testing In Gan Crystalsupporting

confidence: 89%

See 1 more Smart Citation

Elastic–plastic transition during nanoindentation in bulk GaN crystal

Fujikane

Leszczyński

Nagao

et al. 2008

Journal of Alloys and Compounds

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“…During loading, the three curves have a similar trend, accompanied with multiple pop-ins. It can be found that the pop-in is associated with the dislocation slip, as shown in the inset for the indentation on (111) plane, which is in accordance with the results observed in experiments [ 36 , 37 , 38 , 39 ] and simulations [ 34 , 25 ] of other materials. Comparing the three curves, we can also find that pop-in occurs first for indentation on (001) plane, followed by (110) plane and (111) plane.…”

Section: Resultssupporting

confidence: 90%

Molecular Dynamics Simulation on B3-GaN Thin Films under Nanoindentation

Chen

Xiang

et al. 2018

Nanomaterials

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The B3-GaN thin film was investigated by performing large-scale molecular dynamics (MD) simulation of nanoindentation. Its plastic behavior and the corresponding mechanism were studied. Based on the analysis on indentation curve, dislocation density, and orientation dependence, it was found that the indentation depths of inceptive plasticity on (001), (110), and (111) planes were consistent with the Schmid law. The microstructure evolutions during the nanoindentation under different conditions were focused, and two formation mechanisms of prismatic loop were proposed. The “lasso”-like mechanism was similar to that in the previous research, where a shear loop can translate into a prismatic loop by cross-slip; and the extended “lasso”-like mechanism was not found to be reported. Our simulation showed that the two screw components of a shear loop will glide on another loop until they encounter each other and eventually produce a prismatic dislocation loop.

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“…In this respect, nanoindentation has proven to be a powerful technique for probing the information on the mechanical properties of GaN thin films and substrates with characteristic dimensions in the sub-micron regime, such as hardness and elastic modulus, creep resistance, fracture toughness, and adhesion [ 3 - 6 ]. The load–displacement curves also reveal the various structural changes within the indented materials during nanoindentation [ 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Deformation Behavior of Nonpolar GaN Thick Films by Berkovich Nanoindentation

et al. 2009

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In this study, the deformation mechanisms of nonpolar GaN thick films grown on m-sapphire by hydride vapor phase epitaxy (HVPE) are investigated using nanoindentation with a Berkovich indenter, cathodoluminescence (CL), and Raman microscopy. Results show that nonpolar GaN is more susceptible to plastic deformation and has lower hardness thanc-plane GaN. After indentation, lateral cracks emerge on the nonpolar GaN surface and preferentially propagate parallel to the orientation due to anisotropic defect-related stresses. Moreover, the quenching of CL luminescence can be observed to extend exclusively out from the center of the indentations along the orientation, a trend which is consistent with the evolution of cracks. The recrystallization process happens in the indented regions for the load of 500 mN. Raman area mapping indicates that the distribution of strain field coincides well with the profile of defect-expanded dark regions, while the enhanced compressive stress mainly concentrates in the facets of the indentation.

show abstract

‘Pop-in’ phenomenon during nanoindentation in epitaxial GaN thin films on c-plane sapphire substrates

Cited by 36 publications

References 15 publications

Elastic–plastic transition during nanoindentation in bulk GaN crystal

Elastic–plastic transition during nanoindentation in bulk GaN crystal

Molecular Dynamics Simulation on B3-GaN Thin Films under Nanoindentation

Mechanical Deformation Behavior of Nonpolar GaN Thick Films by Berkovich Nanoindentation

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