摘要
The interactions between electrons and phonons play the key role in determining the carrier transport properties in semiconductors.In this work,comprehensive investigations on full electron–phonon(el–ph)couplings and their influences on carrier mobility and thermoelectric(TE)performances of 2D group IV and V elemental monolayers are performed,and we also analyze the selection rules on el–ph couplings using group theory.For shallow n/p-dopings in Si,Ge,and Sn,ZA/TA/LO phonon modes dominate the intervalley scatterings.Similarly strong intervalley scatterings via ZA/TO phonon modes can be identified for CBM electrons in P,As,and Sb,and for VBM holes,ZA/TA phonon modes dominate intervalley scatterings in P while LA phonons dominate intravalley scatterings in As and Sb.By considering full el–ph couplings,the TE performance for these two series of monolayers are predicted,which seriously downgrades the thermoelectric figures of merits compared with those predicted by the constant relaxation time approximation.
基金
This work is supported by the National Natural Science Foundation of China under Grants No.11374063,11674062 and 11404348
the National Key R&D Program of China(2017YFA0303403)
the Shanghai Municipal Natural Science Foundation under Grant No.19ZR1402900
the Natural Science Foundation of Jiangsu Province under grant No.BK20180456
Fudan University-CIOMP Joint Fund(FC2019-006).
