Impact Of Uniaxial Strain And Vacancy Defects On Electronic Properties And Quantum Transport Of Monolayer ?-GeTe

Tunnel field-effect transistors(TFETs)are promising devices for low-power electronics owing to their ability to overcome the Boltzmann limit of 60 mV/decade of subthreshold swing(SS).However,it is a special challenge to enhance the on-state current for TFETs applications.Two-dimensional semiconductor has a smooth surface,the carriers can be limited in the 2D plane,and easily controlled by the gate voltage.Therefore,it is usually considered as the channel material of the TFETs.By means of first-principle calculations and non equilibrium Green' s function(NEGF)method,we systemically investigate the electronic properties of twodimensional monolayer ?-GeTe and discuss the impact of uniaxial strains and vacancy defects on electronic properties.Based on the results of electronic properties,the performance of monolayer ?-GeTe TFET have been explored in detailed.The results show that monolayer ?-GeTe is an indirect band gap semiconductor with high electron mobility.Besides,the band gap transformation from indirect to direct and the mobility of electron along y direction rapid jumption can be observedunder the tensile ratio 2%-5% along the y direction.From the results of transports,it is seen that the OFF current of x direction is one order of magnitude less than these of y direction.The uniaxial tensile strain can dramatically reduce the OFF-current and enhance the ON/OFF ratio under 3%-4% tensile strain along y direction.When the effect of the vacancy defects is considered,It can be found that ON current and ON/OFF ratio of monolayer ?-GeTe TFET of single vacancy reach the require device of high performance(HP)of ITRS predicted and double vacancies of Ge reach the require device of low performance(LP).