First-principles Study Of The Regulation Of Schottky Barriers In Two-dimensional Carbon-Phosphorus Heterojunctions

Two-dimensional nanomaterials,with their excellent physical and chemical properties,have become one of the focal points of research in the fields of physics and materials science in recent years.Due to the difficulty of preparation and poor stability,single-layer 2D materials can rarely be used independently in micro and nano optoelectronic devices.The stacking of 2D monolayers with other materials to form 2D van der Waals（vd W）heterojunctions is a practical solution for the application of 2D materials in optoelectronic devices.When constructing semiconductor-metal heterojunctions,the type of contact formed at the interface directly determines the performance of the FET.The construction of heterojunctions with excellent properties using single layer 2D materials is still one of the challenges in condensed matter physics and materials science.In this paper,the interfacial properties of PC₃（PC₃H）and different metal heterojunctions are systematically investigated based on first-principles calculations,and strategies for effective regulation of interfacial potential barriers are explored,taking two-dimensional semiconductor Carbon-Phosphorus（PC₃,PC₃H）as the research object.The details of the study and the results are as follows:（1）The effects of electric field and biaxial stress on the electronic properties and Schottky barrier heights of PC₃/graphene（G）and PC₃H/G vd W heterojunctions were investigated.The results show that the electric field or biaxial stress has a significant modulating effect on the Schottky barrier at the heterojunction interface.Under an electric field of-0.76 V/nm or 8%stress,the PC₃/G heterojunction interface is tuned from a p-type Schottky contact to an ohmic contact.Hydrogenated PC₃ is an effective strategy to shield part of the applied electric field and make the potential barrier more sensitive to stress,and the barrier height at the PC₃H/G heterojunction interface can be reduced to zero at 4%stress.（2）The effect of a single h-BN intercalation layer on the electronic structure between the metal/PC₃ vd W heterojunction interface has been investigated.It is found that the insertion of an h-BN monolayer between the PC₃-metal interface can achieve the modulation of the Schottky barrier height at the interface.Due to the interaction between PC₃ and metal,the electronic structure of PC₃ is disturbed and the Fermi energy level is fixed at the edge of the PC₃ conduction band.The insertion of a single layer of h-BN between the metal and PC₃interface disrupts the interfacial interaction,restores the electronic structure of PC₃.For the PC₃/Ag（111）and PC₃/Cu（111）interfaces,the insertion of a single layer of h-BN can significantly reduce the height of the barrier at the interface and achieve ohmic contact.