纤锌矿AlN/Al_xGa_(1-x)N/AlN量子阱中界面光学声子对电子迁移率的影响

Influence of Interface-phonon Scattering on Electron Mobility in Wurtzite AlN/Al_xGa_(1-x)N/AlN Quantum Wells

对三元混晶纤锌矿AlN/AlxGa1-xN/AlN量子阱,通过数值自洽求解薛定谔方程和泊松方程,获得二维电子气中电子的本征态和本征能级.利用雷-丁平衡方程,讨论该体系中界面光学声子对电子迁移率的影响.在计算中,对AlxGa1-xN中的体纵声子采用修正的无序元素等位移(MREI)模型,横光学声子则分别采用线性拟合(LF)和二次多项式拟合(QMF)方法,计算获得界面声子对电子的散射作用.结果表明,用LF方法获得的电子迁移率高于用QMF方法计算的值.随着Al组分的增加,两种方法之值均逐渐单调增加,且变化趋势类似.在适当的Al组分时,两种方法得到的电子迁移率都存在极值点.

Adopting a numerical method to solve self-consistently the Schirdinger equation and Poisson equation for wurtzite AlN/AlxGa1-xN/AlN quantum wells including ternary mixed crystals effect,the eigenstates and eigenenergies of electrons in two-dimensional electron gas（2DEG） are obtained.Using the Lei-Ting balance equation,the influence of interface-phonon scattering on electron mobility is discussed.In our calculation,the MREI model is adopted to obtain frequencies of LO phonons,whereas TO phonons in AlxGa1-xN are fitted by the linear fit function（LF） and by quadratic polynomial function（QMF） respectively to calculate the interface phonon scattering on an electron.The results show that the electron mobility calculated by LF method is higher than that by QMF method.The results of electron mobility obtained by the two methods increase monotonically with increasing Al composition,and their varying trends are similar.There exist maximum points in both results by the two methods at appropriate Al compositions.