Monolayer Tin Oxide Strain Engineering Research And Its Application In Gas Sensor

Since graphene was successfully synthesized in 2004,two-dimensional materials have become a hot research object.Since two-dimensional materials have only atomic thickness,they have great application potential in the field of fiery nano-devices today.Similar to three-dimensional materials,two-dimensional materials can be divided into conductors,semiconductors and insulators according to their electrical conductivity.Among them,the research heat of two-dimensional semiconductor materials has been lingering for a long time,and oxide semiconductor materials are one of them.Monolayer SnO was successfully prepared on Si O₂ substrate in 2016.It is a typical P-type two-dimensional semiconductor material and is currently mainly used in P-channel thin film transistors.SnO can be divided into Bulk-like and layered,from Bulk-like shows that a single layer of SnO can be obtained by mechanical peeling.Since the synthesis time of SnO is not short,so there is relatively little research on it.At present,some researchers have studied the performance changes of doping with transition metal elements,but the exploration of possible applications in other aspects is still relatively vacant.This article uses the CASTEP module in the Material Studio software to explore the single-layer SnO based on first principles.First,SnO unit cells were used for structural optimization.After the optimization,the lattice constants of the unit cells were obtained,and the results were completely consistent with those in the literature.Based on the unit cell after optimization,the Hooke's law is combined with the characteristics of the two-dimensional material itself,the system energy is obtained by applying unidirectional different small strains,and a three-dimensional strain energy map is constructed.By fitting the figure,the monolayer SnO is calculated in the ideal Under the state of mechanical performance parameters,such as Young's modulus,Poisson's ratio,in-plane stiffness,etc.,it was found that a single layer of SnO is a soft,hard and moderate wide band gap two-dimensional semiconductor material.Secondly,the effect of biaxial strain control on the performance of single-layer SnO was calculated.The results show that within the range of-12%?12%biaxial strain,SnO is still in the elastic stage,and different strain values can change the energy band value of SnO within a certain range.The effective mass of electrons will also be affected by the strain,but the strain does not affect the characteristic that the effective mass of electrons is isotropic on the x-axis and y-axis.The graphics are all"fan-shaped",but the sizes are different.In addition,the effect of different strains on the electron mobility of SnO was also studied.The results showed that when the strain value increased by 4%,the electron mobility increased slightly,while at the strain value of 8%or 12%,the electron mobility continued to decrease Small,this phenomenon is the same as the change trend of the energy band under different strain conditions calculated by the HSE06 hybrid functional.Finally,this work explores the possible application of SnO in gas sensors.The gas molecules studied include CH₄,CO,CO₂,H₂,H₂O,NH₃,N₂,NO₂,NO,O₂.First,the optimal adsorption site of each gas molecule on the upper part of SnO is determined by calculating the adsorption energy at different positions.Then,by calculating the charge transfer at the optimal adsorption site,energy band and state density and other related properties to determine the adsorption capacity of SnO to different gas molecules.The results show that the monolayer SnO has a strong adsorption capacity for NO,NO₂ and O₂.The reason can be attributed to:after SnO adsorbs these three gas molecules,their distance from the substrate is short,the charge transfer amount is large,and the gas molecules factors such as significant changes in the bond length and bond angle.Compared with arsenic,the response of single-layer SnO to NO and NO₂ is more obvious,and its adsorption capacity for O₂is almost the same as that of WS₂,indicating that monolayer SnO can be used as a sensitive element in gas sensors.I believe that in the near future,there will be more and more research on single-layer SnO,and it will inevitably be able to play a huge application value.