Origin of Nanoscale Incipient Plasticity in GaAs and InP Crystal

Abstract

In this article, we exhibit the influence of doping on nanoindentation-induced incipient plasticity in GaAs and InP crystals. Nanoindentation experiments carried out on a GaAs crystal show a reduction in contact pressure at the beginning of the plastic deformation caused by an increase in Si doping. Given that the substitutional Si defects cause a decrease in the pressure of the GaAs-I → GaAs-II phase transformation, we concluded that the elastic–plastic transition in GaAs is a phase-change-driven phenomenon. In contrast, Zn- and S-doping of InP crystals cause an increase in contact pressure at the elastic–plastic transition, revealing its dislocation origin. Our mechanical measurements were supplemented by nanoECR experiments, which showed a significant difference in the flow of the electrical current at the onset of plastic deformation of the semiconductors under consideration.

Atomic-Scale Friction Studies on Single-Crystal Gallium Arsenide Using Atomic Force Microscope and Molecular Dynamics Simulation

“…10. The indentation hardness is representative of the plastic property of the material and coincides with the value of flow stress obtained in this work from the MD simulation, which possibly suggests that GaAs can flow plastically at a lower stress value than previously reported [38]. Moreover, the stress that is required to cause a phase transformation from GaAs-I to GaAs-II phase is of the order of 17.3 GPa, which is unlikely to occur during nanoscratching [42][43][44].…”

“…A previous experimental work on doped GaAs material indicated the possibility that the phase transition from a zincblende structure (GaAs-I) to a rocksalt structure (GaAs-II) is responsible for the incipient plasticity during its nanoindentation process [38]. Without offering any direct evidence of the phase transition and at pressures as high as < 12 GPa, the work suggested that the GaAs-I to GaAs-II transition causes the plasticity in the material.…”

Understanding Nanoscale Plasticity by Quantitative In Situ Conductive Nanoindentation

“…The indentation‐generated dislocation loops are of the order of ≈10 4 with a critical radius of 2.15 nm for the first pop‐in event to trigger the plastic deformation in InP. [ 274 ] In Chrobak et al's [ 172 ] experiment, the current rise in InP at the pop‐in is two orders smaller than in GaAs (see Figure 19c,d), indicating that the dislocation contribution on the electrical conductivity in InP is minimal. Further, such a slight rise in the electrical current may be due to the sudden increase in the contact area.…”

“…The I-h-t curve for c) GaAs shows a current spike, and d) InP shows an abrupt current rise at the pop-in event. Reproduced under the terms of the CC BY 4.0 license [172]. Copyright 2019, D. Chrobak et al, MDPI Publishing.…”

On Incipient Plasticity of InP Crystal: A Molecular Dynamics Study

“…A review of the scientific literature shows that the optoelectronic properties of InP are basically known, while the cause of its elastic-plastic transition has not yet been fully determined. Looking at the available data, the dominant role of dislocation activity becomes clear in the plastic deformation of InP [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], without the participation of structural phase transformations [ 18 ]. However, the results of mentioned structural investigations were carried out after nanoindentation experiments, so it is premature to exclude the effect of phase transformation on the incipient plasticity of InP.…”