Phonon Limited Mobility Of GeP,SnS(Se) And GeS(Se)

Two dimensional(2D)semiconductors with appropriate band gap have a wide range of applications in optoelectronic field,but their applications are limited by the carrier mobility.Based on the density functional theory,the electron band structure,phonon properties,strain behavior and carrier intrinsic mobility of some new two-dimensional materials are studied by using the longitudinal acoustic phonon deformation potential model,the optical phonon deformation potential model and the electron-phonon coupling matrix element obtained by wannier Fourier interpolation.The main factors affecting the mobility are discussed.For single-layer GeP,the strain behavior and carrier mobility are studied in detail.The results show that Ge P can maintain stable elastic deformation in the armchair direction(x-axis)0-12.9% and zigzag direction(y-axis)0-26.2%.In addition,we also calculate the carrier mobility under different strains.The results show that the hole mobility can be effectively improved when the strain is applied properly on the y-axis,which is mainly due to the decrease of deformation potential.For single-layer SnS and SnSe,it is found that their structures are more stable in the armchair direction than in the zigzag direction by applying uniaxial strain.When the armchair strain increases,the band gap exhibits abnormal behavior,which can be explained by the hybridization of p-state orbital of S or Se atom with that of Snatom.It is found that the hole mobility is mainly determined by acoustic phonon scattering and the electron mobility is mainly determined by optical phonon scattering.The carrier mobility decreases with the increase of tensile strain in armchair direction,which is mainly due to the increase of carrier effective mass.The calculated results show that the mobility can be effectively improved by appropriate compressive strain.For single-layer GeS and GeSe,the carrier mobility is calculated by different models and electron-phonon interaction.Compared with the experimental results,it is found that the traditional deformation potential theory tends to overestimate the mobility,because they only consider the influence of longitudinal acoustic phonon and optical phonon scattering,respectively.In order to accurately predict the carrier intrinsic mobility,we further calculate each electron-phonon coupling matrix element by using the Wannier function interpolation method.For polar semiconductors,Fr(?)hlich interaction is also considered.