纤锌矿氮化物半导体束缚极化子及压力效应

考虑到纤锌矿结构的氮化物半导体材料的单轴异性,采用变分法研究了两支异常光学声子LO-like和TO-like对杂质态结合能的影响,即极化子效应.计及电子有效质量,材料介电常数及晶格振动频率随流体静压力的变化,讨论了束缚极化子结合能的压力效应,数值结果表明,极化子效应使杂质态结合能明显降低,极化子效应的主要贡献来自杂质态与LO-like声子的相互作用.压力使得结合能增加,且增强了结合能的各向异性.

Bound Polaron in Wurtzite Nitrides Semiconductor and Pressure Effect

A variational approach is used to study the polaron effect from both the abnormal optical LO-like and TO-like phonons on the binding energies of impurity states in wurtzite nitrides semiconductor crystals by considering the uniaxial anisotropy.Taking the variations of electronic effective mass,material dielectric constants and crystal lattice vibrational frequencies with hydrostatic pressure into account,the pressure effect on the binding energy of bound polaron is discussed.The numerical results show that the polaron effect obviously decreases the binding energy,and the contributions from impurity-LO-like phonon interaction to the polaron effect are dominant.It is also found that pressure enhances the binding energy and its anisotropy.