First-principles Study On The Electron-phonon Scattering And Mobility In Arsenene,antimonene And Two Dimensional Arsenene/Antimonene(AsSb) Compound

Carrier mobility is an important parameter reflecting the transport properties of semiconductor,while electron-phonon scattering is the main factor that affects the intrinsic transport of hot carriers at room temperature.In this thesis,the first-principles method based on the density functional perturbation theory combining the Wannier interpolation are used to investigate the electron-phonon scattering of Arsenene,Antimonene and two-dimensional?2D?Arsenene/Antimonene compound.The Boltzmann transport equation is used to compute the phonon limited hole and electron mobilities of 2D AsSb compound.The main results are summarized as below:?1?We first analyzed the electronic structure of Arsenene and Antimonene,then compared the electron-phonon scattering of the two-dimensional materials.Based on the results of electron-phonon scattering,we further compared the carrier relaxation time and the mean free paths of the two systems.The results show that the scattering rates of the two structures have the same trend,at the valence band maximum?VBM?and the conduction band minimum?CBM?,the scattering rate has a minimum value,and the scattering rates increase away from the band edge.Furthermore,we also study the influence of optical phonon and acoustic phonon on relaxation time.The results show that the acoustic phonons have the larger relaxation time at the VBM in two structures,and the maximum values in arsenene and antimonene are 144 fs and 250 fs,respectively.While the optical phonons have the larger relaxation time at the CBM,the results are 38 fs and 35 fs,respectively.The mean free paths of hot hole and electron in the two systems are 8,21nm and 7,22nm.?2?We investigated the electron-phonon scattering of 2D AsSb compound,and analyzed the influence of six phonon modes on the scattering rates and relaxation time in detail.On this basis,the carrier mobilities are calculated.It is found that the optical phonon branches are much larger than acoustic ones around VBM and CBM.The phonon-decomposed scattering results show that transverse optical?TO?phonon mode has larger effect on scattering than the other five phonon modes around VBM,while longitudinal and out-of-plane acoustic modes contribute mostly to the scattering than other phonon modes away from the band edge.TO phonon modes are the main factor that influences the scattering for electrons over all energy level,and the electron-phonon matrix element analysis verified the results.We observed that the best extract range for hot elelctrons and hot holes in this 2D compound material are 8nm and 20 nm,respectively.Owing to the in-pane net dipole moment of 2D AsSb,the intrinsic electron?hole?mobility of AsSb are 38?50?cm²?V^-1?s^-1,which are less than arsenene and antimonene.