Dislocation cross-slip in GaN single crystals under nanoindentation

Huang, Jingyi; Xu, Ke; Gong, Xiaojing; Wang, J. F.; Fan, Yujie; Liu, J. Q.; Zeng, Xionghui; Ren, Guoqiang; Zhou, T. F.; Yang, Hui

doi:10.1063/1.3593381

Cited by 68 publications

(56 citation statements)

References 16 publications

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“…In the case of monochromatic measurements, freshly introduced screw dislocations in the exciton CL band had dark contrast as reported previously [8,9,17]; in the panchromatic mode, the bright con trast of screw dislocations reached 20-30% at an accelerating voltage of V a = 5 kV. We note that images of deeper curvilinear dislocation loops appeared in the CL maps near the growth surface indents at high accelerating voltages, which were seen as dark lines with a contrast of 2.5-5% in all modes in accordance with previously published data [18].…”

Section: Resultsmentioning

confidence: 58%

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

2015

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Section: Resultsmentioning

confidence: 58%

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

2015

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“…Under highly constrained loading con ditions, slip is sometimes observed on the < 1 1 2 3 > {1122} and < 1120 > {1101} pyramidal slip systems, such as in the micropil lar tests of Wheeler et al [19] where the loading was such that no significant shear stress was applied on the basal and prismatic slip systems, or in nano-indentation tests [37]. Under highly constrained loading con ditions, slip is sometimes observed on the < 1 1 2 3 > {1122} and < 1120 > {1101} pyramidal slip systems, such as in the micropil lar tests of Wheeler et al [19] where the loading was such that no significant shear stress was applied on the basal and prismatic slip systems, or in nano-indentation tests [37].…”

Section: Extension To Multislipmentioning

confidence: 99%

Constitutive Relations for Modeling Single Crystal GaN at Elevated Temperatures

Maniatty

Karvani

2014

Journal of Engineering Materials and Technology

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P ro fe sso r F e llo w A S M E D epartm ent o f M e c h a n ic a l, A erospace, and N ucle a r E n g in e erin g, R ensselaer P o ly te c h n ic In stitute, T ro y, N Y 1 2 1 8 0 -3 5 9 0 e -m a il: m a nia a @ rp i.e d u P aym an KarvaniM e m . A S M E D epartm ent o f M e c h a n ic a l, A erospace, and N ucle a r E n g in e erin g, R ensselaer P o ly te c h n ic In stitute, T ro y, N Y 1 2 1 8 0 -3 5 9 0 e -m a il: p ay m a a n @ g m a il.c o m Constitutive Relations for Modeling Single Crystal GaN at Elevated TemperaturesThermal-mechanical constitutive relations for bulk, single-crystal, wurtzite gallium nitride (GaN) at elevated temperatures, suitable for modeling crystal growth processes, are pre sented. A crystal plasticity model that considers slip and the evolution o f mobile and immo bile dislocation densities on the prismatic and basal slip systems is developed. The experimental stress-strain data from Yonenaga and Motoki (2001, "Yield Strength and Dislocation Mobility in Plastically Deformed Bulk Single-Crystal GaN," J. Appl. Phys., 90(12), pp. 6539-6541) for GaN is analyzed in detail and used to define model parameters for prismatic slip. The sensitivity to the model parameters is discussed and ranges for pa rameters are given. Estimates for basal slip are also provided.

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“…Bhattacharya et al [9] studied the effect of loading rate on the nanohardness of sapphire. Numerous studies have investigated the nanomechanical properties of some other single-crystal materials [10][11][12][13]. These studies have been predominantly conducted at the nanometer scale, which is more representative for precision machining.…”

Section: Introductionmentioning

confidence: 99%

Effects of Crystal Orientation on the Crack Propagation of Sapphire by Sequential Indentation Testing

Wang

Jiang

et al. 2017

Crystals

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Single-crystal sapphire (α-Al 2 O 3) is a hard and brittle material. Due to its highly crystalline nature, the fracture behavior of sapphire is strongly related to its crystal structure, and understanding the effects of crystal structure on the crack propagation of sapphire is essential for the successful application of this important material (e.g., as wafers in the electronics industry). In the present work, crack propagation that is induced by sequential indentation was investigated on the A-plane and C-plane of sapphire using a Vickers indenter on a micrometer scale. It was found that increasing indentation depth obviously increases the rate of crack propagation on the A-plane, but this effect is not so obvious on the C-plane because of the different slip systems induced by indentation on the different crystal planes of sapphire. Moreover, some parallel linear traces along the A-plane, which fracture with increasing indentation depth, are observed from the residual indentation on the A-plane. The fracture toughness of both A-plane and C-plane sapphire is smaller after indentation testing than that obtained using conventional testing methods. The subsurface damage was detected by transmission electron microscopy (TEM).

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Dislocation cross-slip in GaN single crystals under nanoindentation

Cited by 68 publications

References 16 publications

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

Constitutive Relations for Modeling Single Crystal GaN at Elevated Temperatures

Effects of Crystal Orientation on the Crack Propagation of Sapphire by Sequential Indentation Testing

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