Influence of point and linear defects on thermal and mechanical properties of germanium nanowire: a molecular dynamics study

In the nanoscale dimensions, semiconductor nanowires such as germanium nanowires (GeNWs) are appropriate candidates for using field-effect transistors, Josephson junctions, sensors and so on. However, such uses require detailed knowledge of the physical properties of GeNW. Thus we investigated the thermal conductivity and stress-strain diagram of GeNW with lattice vacancy and linear imperfection. Non-equilibrium molecular dynamics simulation as numerical method was employed in this research. The three body Tersoff potential was employed to describe interaction between germanium atoms in GeNW. Two types of defects, point and linear, were applied to the nanowire. The Nose-Hoover thermostat was employed to control temperature of the system. We then studied thermal conductivity and Young’s modulus in three crystallography directions [100], [110] and [111]. Our MD results showed that in the case of 8% point vacancy, the thermal conductivity decreased greater than 70% and Yong’s modulus decreased about 25% for three crystallography directions.