| Graphene,a two-dimensional nanomaterial with unique physical structure and excellent electronic properties,has become the first two dimensional nanomaterial prepared by mechanical stripping.But,a large number of studies have found that the band gap of graphene is zero,and the current switch ratio is extremely low,these defects limit its application in modern electronic industry.In this case,researchers begin to study a new 2D material-phosphorene.Phosphorene was successfully stripped from massive phosphorus and had strong in-plane anisotropy,including energy band structure,mechanical properties,electrical conductivity,thermal conductivity and photoelectric response.In addition,the study also predicts that phosphorene has a direct gap,and the band gap varies with the thickness of the phosphorene layer,ranging from 0.8 to 2 eV.In addition,it is reported that the carrier mobility of up to 103 cm2 V-1 S-1 and the switching ratio of104 at room temperature are reported.Not only that,many studies have revealed other useful properties of phosphorene.These excellent performances show that:compared with graphene,phosphorene is a promising two-dimensional semiconductor material,and has potential for wide application of field-effect transistors and thin film solar cells.This article mainly explores the influence of adsorption of small molecules and the width of zigzag direction on the electronic properties and transport properties of phosphorene.The results of this study are as follows:1:The first principle based on the density functional theory has been used to study on the electronic properties of phosphorene bilayer with physical adsorption of small molecules,these molecules including carbon monoxide?CO?,hydrogen?H2?,water?H2O?,ammonia?NH3?,nitric oxide?NO?,nitrogen dioxide?NO2?and oxygen?O2?.The results show that:?1?CO,NH3,NO and O2 molecules act as charge donors,while H2O,H2 and NO2 molecules act as charge receptors.?2?the reaction of O2 molecules with phosphorene bilayer is the strongest in all the studied gas molecules.?3?physically adsorbed gas molecules can produce significant charge transfer on phosphorene bilayers.This not only enables phosphorene to be applied to gas sensors,but also provides an effective way to change the polarity of phosphorene.?4?Not only the band structure of phosphorene is changed by the adsorption of gas molecules,but also the NO,O2 and NO2adsorbed phosphorene bilayers exhibit magnetism,,and NO?O2?adsorbed phosphorene bilayer is a typical n?p?type semiconductor.?5?in addition,along with the increasing of the external electric field,the band gap of phosphorene bilayer adsorbed with CO/H2O decreases,this phenomenon indicates that applied external electric field can effectively change the electronic properties of phosphorene,also broaden the application of phosphorene in Nano Electronics and photonic devices.2:This article also mainly discusses the changes in the electronic structure and transport properties of the zigzag nanoribbons with oxygen atoms passivated with the change of the bandwidth.Our study shows that:?1?To the zigzag O–passivated phosphorene bilayer,the variety of width will affect the electronic properties of nanoribbons,when the width is 2,4 nm,with a direct band gap is smaller than that of ideal phosphorene.When the band width increases,the nanoribbon shift from a direct band gap semiconductor to a metal.?2?With the increase of bandwidth,the negative resistance behavior appears.When the bandwidth is 6,the negative resistance behavior is most obvious.?3?When the bias voltage is less than 1.1V,the transport properties of 6-zigzag O-passivated nanoribbons is stronger,but when the bias pressure is higher than 1.4V,the transport properties of the 8-zagzig O-passivated zagzig nanoribbons are stronger. |
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