Tunable Electronic Properties And Electric-Field-Induced Phase Transition In Phosphorene/Graphene Heterostructures

The shortcomings of mono-component systems e.g. the gapless nature of graphene, the lack of air-stability in phosphorene, etc, have drawn great attention toward stacked materials that are expected to show interesting electronic and optical properties. Using a tight-binding approach and a Green's function method, we investigate the electronic properties of armchair-edged lateral phosphorene-graphene heterostructures, which are either semiconductor-semiconductor or semiconductor-metal heterostructures, depending on the width of the graphene ribbon. It is found that the system is narrow-gapped, and that the bandgap can be modulated by tuning the sizes of the domains. Besides, an analysis of the bandgap variation versus the width of the component phosphorene ribbon indicates that, in a semiconductor-metal heterostructure, a phosphorene ribbon does not induce any electronic state near the Fermi level, suggesting that the suppressed electron transport should be attributed to hole transfer across the interface. Furthermore, we show that a transverse electric field can significantly diversify the electronic behavior of a heterostructure i.e. the heterostructure undergoes a semiconductor-metal phase transition. Moreover, tuning the transverse electric field yields the intriguing possibility that the system can undergo a topological phase transition from a band insulator to a topological insulator.