介电常数的修正对半导体异质结中杂质态结合能的影响

采用连续电介质理论计入对材料介电常数的修正,利用变分法讨论半导体单异质结中界面附近的单电子束缚于施主杂质的基态结合能.对A lxG a1-xA s/G aA s和G axIn1-xN/InN等几种半导体异质结做了数值计算,给出杂质态结合能随杂质位置的变化关系.结果表明:当杂质处于垒材料中远离界面时,介电常数的修正对结合能无明显影响;当杂质靠近界面且组成异质结的两种材料的介电常数相差较大时,计入修正后的结合能低于已有的近似结果,最大降低可达5%~6%(x=0.3).

Influence of Modification of Dielectric Constants on the Binding Energies of Impurity States in Semiconductor Heterojunctions

A variational method is adopted to investigate the ground state binding energy of an electron bound to a donor impurity near the interface of a single semiconductor heterojunction by considering the modification of the dielectric constant within a continuous dielectric theory.The binding energies of impurity states as functions of the impurity position are obtained numerically for several semiconductor heterojuncions such as Al_xGa_(1-x)As/GaAs and Ga_xIn_(1-x)N/InN.It is shown that the modification of dielectric constant does not obviously influence the binding energy when the impurity is localized far away from the interface,whereas the binding energy is lower than the former approximated result when the impurity is localized near the interface and the difference between the dielectric constants of the two materials is larger.The largest decrease is 5%~6% for x=0.3.