| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 104 === Mechanical and fracture behaviors of GaP nanowires (NWs) in zinc-blende and wurtzite phases were investigated by Molecular dynamics simulations using the program package LAMMPS with Tersoff potential. Simulation was performed and focused on the effects of different structure, orientation, length, temperature and diameter on the behaviors of slip system, strength, stress distribution and fracture process of NWs under uniaxial tension. The results show that the magnitude of Young’s modulus of zinc-blende GaP NWs in [111] orientation is greater than [110] and [001], while [001] is the smallest. For zinc-blende [111] and wurtzite [0001] GaP NWs with different cross-sectional shape, the magnitude of Young’s modulus of square is higher than the hexagon. On the other hand, size effect of the NWs is significant. The magnitude of Young’s modulus and fracture stress of zinc-blende GaP nanowires decreases with the decrease of diameter. However, the magnitude of Young’s modulus and fracture stress of wurtzite GaP nanowires has no such a monotonic relation. In addition, the fracture stress of both zinc-blende and wurtzite GaP NWs increases with decreasing temperature and strain rate and with increasing length of NWs. Viewing from the cross-section, the fracture of zinc-blende and wurtzite GaP NWs individually initiates from the corner and the side of the outer surface. Specially, the strength of the NWs in wurtzite structure is higher than in zinc-blende structure.
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