Electron Transport And Photoelectric Properties Of Novel Semiconductor Materials And Its Heterostructures

Two-dimensional(2D)Graphene,a material with 2D honeycomb structure and excellent mechanics and electromagnetic propertieshas captured widespread attention as a potentially promising material for developing spintronic and electronic devices.However,pristine graphene is a zero-bandgap semi-metal,which is significantly restricted in practical applications,and it became important to manipulate these properties by introducing defects and atoms terminated.At the same time,the new non-carbon 2D atomic crystalline materials,such as phosphorene,silicene,and transition metal dichalcogenides etc.,have been successfully fabricated and applied to photovoltaic devices such as photovoltaic devices and field-effect transistors.There are still some shortcomings in the material.It is necessary to further explore the properties of two-dimensional materials.In this paper,first-principles calculation methods are used to substitute one-dimensional arsenene nanoribbons.The electronic structure and electron transport properties of nanoribbons are studied.The van der Waals(vdW)heterostructures such as SnC/BAs,BAs/arsenene and antimonene/C2N are designed by first-principles method,and their electronic structure and optical performance are adjusted by external electric field and apply strain.The research was carried out in order to provide reference for the practical application of new nanomaterials in nanoelectronic devices,optoelectronics and other fields.First,the domestic and international research status and application prospects of two-dimensional materials in experiments and theory are introduced.The arsenene nanoribbon model was hydrogen-saturated at the edges,and its stability was proved by formation energy and molecular dynamics simulations.By replacing a arsenic atom with a transition metal manganese(Mn)atom to induce the magnetism of the system.The calculation results show that the different doping positions of the Mn atoms make the arsenene nanoribbons appear magnetic and is beneficial to the design of spin electronic devices.After applying external electric field control,AAsNR-Mn experienced a transition from semi-semiconductor to semi-metal.In addition,it has excellent magnetic device characteristics,and shows perfect spin filtering effect(SFE)to 100%after designing as an electronic device,and its giant magnetoresistance(GMR)is close to 106%.Our calculations show that AAsNRs-Mn has broad application prospects in multifunctional spintronic devices.Subsequently,we began to consider the possibility of a two-dimensional material vdw heterostructure,and designed a vdw heterostructure formed by a single layer stack of SnC and BAs.After considering the adaptation rate and different stacking methods,we simulated the stability of the material.In contrast to the single layer,the electronic structure of the heterostructure has a type II band alignment and a direct band gap of 0.22eV,which is beneficial to the separation of photogenerated electron-hole pairs.The method of applying vertical strain and external electric field regulation is adopted to show that the band gap changes greatly and undergoes indirect to direct band gap transitions,effectively adjusting the band gap.In addition,the band gap of the heterostructure changes linearly with the external electric field,and the semiconductor-to-metal transition can be achieved in the presence of a strong electric field.The calculated band arrangement and light absorption show that the SnC/BAs heterostructure can exhibit excellent light collection performance.The heterostructures we design are expected to find applications in nanoelectronic devices,photovoltaics,and optical properties.Next,we also considered the van der Waals heterostructure formed by the 2D ?-arsenene and BAs single-layer heterostructure.The four possible stacking methods of the heterostructure were simulated and calculated.The most stable HT-stacking stacking was selected for Calculation of electronic characteristics.The results show that the band gap of the BAs/arsenene heterostructure is sensitive to electric field regulation and can make the band alignment mode change in type ? and type ?.After the vertical strain is applied,the band gap of the heterostructure plays a regulating role and promotes the separation of electrons and holes in the heterostructure.It is expected to be used in electronic devices.On the other hand,the calculation results of the external electric field and vertical strain for the light absorption of the heterostructure undergo significant red and blue shifts,and the absorption peaks become larger and wider.It also shows that the BAs/arsenene vdw heterostructure has great potential in the field of photovoltaic device applications.Finally,for the antimonene/C2N heterostructure formed by the fifth main group 2D?-antimonene and multi-empty C2N monolayer,three different stacking models were designed and the lowest energy was selected as an example.The calculation results show that the he heterostructure band gap is much smaller than the isolated single-layer band gap.Also the energy band structure of system is type ? energy band alignment,which electrons and holes are accumulated in C2N and antimony layer,respectively.At the same time,the two factors of external electric field and interlayer spacing have corresponding band gap effects on the heterostructure and good control of the optical properties,indicating that the antimonene/C2N heterostructure has application potential in optoelectronic devices.