Browsing by Author "Chiu, Yi-Jui"

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Localized Deformation and Fracture Behaviors in InP Single Crystals by Indentation
(2018-12-01)
Chiu, Yi-Jui
;
Jian, Sheng-Rui
;
Liu, Ti-Ju
;
Phuoc Huu Le
;
Juang, Jenh-Yih
The indentation-induced deformation mechanisms in InP(100) single crystals were investigated by using nanoindentation and cross-sectional transmission electron microscopy (XTEM) techniques. The results indicated that there were multiple pop-in events randomly distributed in the loading curves, which were conceived to arise primarily from the dislocation nucleation and propagation activities. An energetic estimation on the number of nanoindentation-induced dislocations associated with pop-in effects is discussed. Furthermore, the fracture patterns were performed by Vickers indentation. The fracture toughness and the fracture energy of InP(100) single crystals were calculated to be around 1.2 MPam(1/2) and 14.1 J/m(2), respectively.
The Indentation-Induced Pop-in Phenomenon and Fracture Behaviors of GaP(100) Single-Crystal
(2019-11-01)
Chiu, Yi-Jui
;
Jian, Sheng-Rui
;
Lee, Jyh-Wei
;
Juang, Jenh-Yih
;
電子物理學系
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 K-C of GaP(100) single-crystal was similar to 1.7 +/- 0.1 MPa.m(1/2), which is substantially higher than the K-IC values of 0.8 MPa.m(1/2) and 1.0 MPa.m(1/2) previously reported for of single-crystal and polycrystalline GaP, respectively.