Molecular Dynamics Study of the Mechanical Properties of Germanium Reinforced with Iron Nanoparticles at Different Speeds and Sizes

Germanium (Ge) nanowires are attractive for nanoelectronic and optoelectronic devices due to their narrow bandgap, high carrier mobility, and infrared sensitivity. However, their relatively weak mechanical strength compared to silicon nanowires hinders broader applications. This study proposes a reinforcement strategy for Ge nanowires by incorporating iron (Fe) nanoparticles and systematically evaluates the influence of nanoparticle motion and size on mechanical behavior using molecular dynamics simulations. Ge nanowires with different cross-sectional areas were subjected to uniaxial tensile loading after interacting with Fe nanoparticles. The results indicate that nanoparticle motion reduces system potential energy, enhances atomic bonding, and improves both Young's modulus and ultimate tensile strength. An optimal nanoparticle velocity of 0.005 Å/ps increased Young's modulus from 108 to 119 GPa without causing structural instability, while nanoparticle size exhibited minimal effect. Moreover, the temperature effects on the mechanical properties of reinforced Ge nanowires maintained superior performance up to 700 K.