First-principles Study On The Optoelectronic Properties Of Antimonene-based Van Der Waals Heterostructures

Two-dimensional semiconductor terpenes have attracted extensive attention due to their excellent optoelectronic properties.However,its indirect band gap and wide band gap defects greatly limit its application in the field of optoelectronics.The development of van der Waals heterojunctions with high stability,suitable bandwidth,direct bandgap and high absorption efficiency has become a key issue in the search for materials for high efficiency optoelectronic devices.This paper is based on the first-principles calculation of density functional theory,based on lattice matching,moderate band gap and unique honeycomb structure,and through substrate type,substrate reconstruction,stacking position and stacking layer number.Different kinds of non-alkenyl van der Waals heterojunction structures were designed.The internal structure,band structure and optical properties were systematically studied.The effects of interface effects and stress on the optoelectronic properties of the nonalkenes van der Waals heterojunction were revealed.And the van der Waals heterojunctions with high stability,broad spectral absorption and high visible light absorption coefficient have been explorated.1.The edge reconstruction and edge-dependent electronic properties of a single-layered GaSe semiconductor were investigated.The results demonstrate that both Ga-and Se-terminated zigzag edges prefer to the(3×1)reconstructions,and the armchair edges with the perfect flat configuration are energetically favorable.It is unexpectedly found that both zigzag and armchair GaSe nanoribbons with the reconstructed edges are semiconductors,which is different from previous recognition where the zigzag edges are metallic.Moreover,the edge-dependent flake shape in GaSe has been plotted by using Wulff construction theory,and the shape evolution with chemical potentials can be applied to explain broad experimental observations on the morphologies of GaSe flakes.Importantly,similar reconstructions and electronic properties also appeared at InSe edges,suggesting that the reconstruction induced semiconducting edges are a fundamental phenomenon for 2D group-III metal monochalcogenides.2.Interface effect on electronic and optical properties of antimonene/GaAs van der Waals heterostructures was investigated.The results demonstrate that the vdW interaction is crucial for the stability of Sb/GaAs heterointerfaces,but the interfacial coupling strength and band-structure characteristic of the heterostructures are strongly affected by the interface structures.We find that all stable Sb/GaAs heterostructures exhibit a type-II band alignment and have the relatively small band gaps(0.71~1.39 eV)as compared to that of independent Sb monolayer and GaAs substrates.Moreover,the formation of Sb/GaAs vdW heterostructures can lead to the separation of carriers and high optical absorption coefficient at the visible-light range,which makes Sb/GaAs heterostructures as a potential candidate for the optoelectronic devices,such as solar cells.3.The effects of stress on the optoelectronic properties of the antimonene/germanium vdW heterostructures were investigated.The results show that the stress plays an important role in the electronic properties of the Sb/Ge heterostructures,but the stress and electronic properties are not monotonic,and the band gap decreases with the stress enhancement.During the stress stretching process,the electronic structure of the Sb/Ge heterostructures is changed from type II to I-type,and the carrier mobility is enhanced,and the heterojunction is exhibited high hole mobility and ultra high electron mobility.In addition to excellent electronic properties,Sb/Ge heterostructures also exhibit significant absorption in the visible light spectrum and high light capture potential.This makes Sb/Ge heterojunctions have broad application prospects in the fields of electronics and optoelectronics.