纤锌矿氮化物半导体中电子-声子相互作用对表面电子态的影响(英文)

Electron-Phonon Interaction Effects on the Surface States in Wurtzite Nitride Semiconductors

采用变分法研究了半无限纤锌矿氮化物半导体中电子表面态问题.计及电子与表面光学声子相互作用和结构异性的影响导出了系统的有效哈密顿量,获得了电子表面态能级、电子与表面光学声子相互作用能量分别随表面势垒的变化关系.对GaN,AlN和InN进行了数值计算.结果表明,电子与表面声子的相互作用使电子的表面能级下降,并且纤锌矿结构的GaN和AlN中电子-声子相互作用能量较闪锌矿结构大,而对InN情况正好相反.在计算的所有材料中纤锌矿材料的电子表面能级比闪锌矿的低几百meV.电子与表面光学声子相互作用对表面电子态的影响不应被忽略.

A variational approach is used to study the surface states of electrons in semi-infinite wurtzite nitride semiconductors. The effective Hamiltonian and the surface state levels are derived by taking the effects of the electron-Surface- Optical-phonon （e-SO-p） interaction and structure anisotropy into account. The numerical computation has been performed for the energies of the electronic surface states as a function of the surface potential V0for wurtzite GaN,AlN and InN,respectively. The results show that the electron-phonon （e-p） interaction lowers the surface state levels,and the e-p interaction energies in wurtzite GaN and AlN are bigger than that in the corresponding zinc-blende one,but for InN, the case is contrary. It is also found that the electronic surface-state levels in wurtzite structures are lower than that in the zinc-blende materials for hundreds of meV for the materials calculated. The influence of e-p interaction on the surface states can not be neglected.