Abstract
The deformation behaviors and fracture features of GaP(100) single-crystal are investigated by using nano- and micro-scale indentation techniques. The hardness and Young’s modulus were measured by nanoindentation using a Berkovich diamond indenter with continuous contact stiffness measurements (CSM) mode and the values obtained were 12.5 ± 1.2 GPa and 152.6 ± 12.8 GPa, respectively. In addition, the characteristic “pop-in” was observed in the loading portion of load-displacement curve, which was caused by the nucleation and/or propagation of dislocations. An energetic estimation methodology on the associated nanoindentation-induced dislocation numbers resulting from the pop-in events was discussed. Furthermore, the Vickers indentation induced fracture patterns of GaP(100) single-crystal were observed and analyzed using optical microscopy. The obtained fracture toughness KC of GaP(100) single-crystal was ~1.7 ± 0.1 MPa·m1/2, which is substantially higher than the KIC values of 0.8 MPa·m1/2 and 1.0 MPa·m1/2 previously reported for of single-crystal and polycrystalline GaP, respectively.
Highlights
The III–V zincblende GaP is one of the most widely utilized substrates for fabricating various semiconducting and magnetic thin films [1,2,3,4]
From the viewpoint of device applications, it is of crucial importance to fully recognize the response of substrates due to mechanical stresses introduced during fabrication processes, which might cause the contact-induced damage and cracking
Nanoindentation has been proved to be a powerful tool for studying the fundamental mechanical properties of various nanostructured materials [5,6,7], biomaterials [8,9], and thin films [10,11,12,13,14]
Summary
The III–V zincblende GaP is one of the most widely utilized substrates for fabricating various semiconducting and magnetic thin films [1,2,3,4]. In order to implementing the important functional components of the devices on the GaP substrates, an accurate measurement of its mechanical characteristics is highly demanded. The “pop-in” behaviors have been attributed otherwise to the crack nucleation and the delamination phenomena [24]. In some cases, it has been interpreted as the manifestations of the dislocation activity [18,19,20] depending strongly on the crystal structure of the test materials [25], temperature [26], the shape of indenter tip [27] and indenter angle [28]. The correlations between pop-in behaviors and dislocation activities of materials have been widely studied by combining microstructural observations with the cross-sectional transmission electron microscopy in recent years [29,30,31]
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