Anisotropic crystal orientations dependent mechanical properties and fracture mechanisms in zinc blende ZnTe nanowires

ASMJ Islam and MS Islam and MS Hasan and K Hosen and MS Akbar and AG Bhuiyan and J Park, RSC ADVANCES, 13, 22800-22813 (2023).

DOI: 10.1039/d3ra03825d

The orientations of crystal growth significantly affect the operating characteristics of elastic and inelastic deformation in semiconductor nanowires (NWs). This work uses molecular dynamics simulation to extensively investigate the orientation-dependent mechanical properties and fracture mechanisms of zinc blende ZnTe NWs. Three different crystal orientations, including 100, 110, and 111, coupled with temperatures (100 to 600 K) on the fracture stress and elastic modulus, are thoroughly studied. In comparison to the 110 and 100 orientations, the 111-oriented ZnTe NW exhibits a high fracture stress. The percentage decrease in fracture strength exhibits a pronounced variation with increasing temperature, with the highest magnitude observed in the 100 direction and the lowest magnitude observed in the 110 direction. The elastic modulus dropped by the largest percentage in the 111 direction as compared to the 100 direction. Most notably, the 110-directed ZnTe NW deforms unusually as the strain rate increases, making it more sensitive to strain rate than other orientations. The strong strain rate sensitivity results from the unusual short-range and long-range order crystals appearing due to dislocation slipping and partial twinning. Moreover, the 111 plane is the principal cleavage plane for all orientations, creating a dislocation slipping mechanism at room temperature. The 100 plane becomes active and acts as another fundamental cleavage plane at increasing temperatures. This in-depth analysis paves the way for advancing efficient and reliable ZnTe NWs-based nanodevices and nanomechanical systems.

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