▎ 摘　　要

We investigate the separation of helium isotopes by quantum tunneling through graphene nanopores, recently proposed as an alternative to conventional methods for He-3 production. We propose here a novel defective nanopore created by removing two pentagon rings of a Stone Thrower-Wales (STW) defect, which significantly decreases the helium tunneling barrier by 50-75%. The barrier height is fine-tuned by adjusting the effective pore size, which is achieved by pore rim passivation using an appropriate functionalizing atom. This fine-tuning leads to positive deviation in the tunneling probability of He-3 compared to that of He-4 in the low-energy region, and thereby to high selectivity and transmission of the former isotope. It is found that fluorine-passivated nanopores restrict helium atom penetration of their highly reduced pore size. Defective nanopores in nitrogen- and oxygen-passivated structures exhibit relatively high transmission values of 10(-3) for the oxygen variant and improved selectivity value of 669 for the nitrogen variant. It is demonstrated that defective nanopores passivated on both sides with oxygen are the most attractive for He-3/He-4 separation on the basis of their much higher flux values while still providing good selectivity.