Early stages of mechanical deformation in indium phosphide with the zinc blende structure

Abstract

Nanoindentations were performed on a cubic semiconductor using a cono-spherical diamond tip with a 260 nm radius. The tip produces a single point of contact with the crystal surface allowing indentations with nano-scale dimensions. The early stages of deformation on (100) InP with the zinc-blende structure were observed to happen by the sequential introduction of metastable dislocation loops along the various slip planes directly beneath the point of contact. Locking of the dislocations loops forms a hardened region that acts as an extended tip during subsequent indentation, eventually leading to multiple bulk-like displacements (pop-in events) and to material pile up in the vicinity of the indentation pit. The first pop-in marks the transition of deformation from the nanometer to the micrometer scale.

Localized Deformation and Fracture Behaviors in InP Single Crystals by Indentation

“…Such massive dislocation activities are also consistent with the conjectures of the resultant “noisy” features seen in the depth-dependent curves of hardness and Young’s modulus (Figure 1b,c), as well as those reported by Almeida et al [32] and Jian et al [22]. The multiple “pop-in” behaviors had also been observed in Reference [32]. From Figure 1a, the first “pop-in” is observed on the loading curve at a load of about 0.08 mN in the present work, which is substantially smaller than that (~0.2 mN) reported previously by Almeida et al [32].…”

“…Within the dominant deformation mechanism in the context of dislocation, the multiple “pop-ins” (indicated by the arrows in Figure 1a) can be regarded as the trigger of sudden collective activities of dislocation [29,30,31] (such as dislocation generation or movement bursts), giving rise to the seemingly discontinuous plastic deformation during nanoindentation. Such massive dislocation activities are also consistent with the conjectures of the resultant “noisy” features seen in the depth-dependent curves of hardness and Young’s modulus (Figure 1b,c), as well as those reported by Almeida et al [32] and Jian et al [22]. The multiple “pop-in” behaviors had also been observed in Reference [32].…”

“…The multiple “pop-in” behaviors had also been observed in Reference [32]. From Figure 1a, the first “pop-in” is observed on the loading curve at a load of about 0.08 mN in the present work, which is substantially smaller than that (~0.2 mN) reported previously by Almeida et al [32]. It is noted that the indenter used in Reference [32] was a cono-spherical-type tip with a radius of ~260 nm equipped in a Hysitron Triboscope nanoindenter system.…”

“…From Figure 1a, the first “pop-in” is observed on the loading curve at a load of about 0.08 mN in the present work, which is substantially smaller than that (~0.2 mN) reported previously by Almeida et al [32]. It is noted that the indenter used in Reference [32] was a cono-spherical-type tip with a radius of ~260 nm equipped in a Hysitron Triboscope nanoindenter system. It is possible that different operating modes, indenter geometrical shapes, and size of radius may lead to the vastly dissimilar nanoindentation results.…”

The effect of nanoscratching direction on the plastic deformation and surface morphology of InP crystals

“…These dislocations propagate simultaneously along the various slip planes, forming locks at their intersections and producing a workhardened region with an inverted pyramidal shape and a high density of dislocation loops immediately below the tip. 20 The hardened pyramidal region acts as an effective tip generating elongated dislocation loops in symmetric bands that propagate deep into the crystal. From this perspective, the contribution of the normal force to the scratch morphology is expected to be independent of the scratch direction.…”