Enhancement of mechanical properties of InSb through twin boundary engineering

Abstract

Twin boundaries (TBs) have been found to be an effective strategy in enhancing mechanical properties of semiconductors. Our previous first principles study proved that TBs can raise the ideal strength of thermoelectric semiconducting InSb. In order to further optimize the mechanical properties of InSb, here we studied the role of TB orientation α, spacing λ, and doping in the strength and toughness of InSb. TB orientation behaves with three different deformation modes, including the stacking, slippage cross TBs, and slippage along TBs. When the deformation mode is the slippage cross TBs, TB spacing can enhance the ideal strength corresponding to the Hall-Petch effect. We found that the ideal strength of nano-twinned InSb with α = 43.31° and λ = 1.12 nm can be optimized to be 56.2% higher than its single crystal. These findings will be helpful in guiding the TB design for better mechanical properties of InSb.