摘要
研究双势垒ＧａＡｓ／ＡｌＧａＡｓ结构在与时间有关的交变电场的作用下电子间接共振隧穿的几率和隧穿电流密度。采用转移矩阵方法给出电子在不同空间位置的波函数，用微扰的方法求出电子波函数的含时系数，最终给出电子隧穿几率和隧穿电流密度、计算结果表明电子隧穿几率曲线中出现附加的隧穿峰和隧穿峰变低，并且随穿电流密度曲线巾出现附加的隧穿台阶，隧穿峰变低和展宽，这主要是由于外加突变电场与Ｅ±ｎω的电子态耦合，为电子隧穿提供间接的通道和路径、这也是设计双势垒电子隧穿器件不可忽略的、上述方法也可以推广到多量子阶系统。
Resonant tunneling through semiconductor double barrier has received much attention. Advances in the techniques of building semiconductor heterostructures have stimulated both experimental and theoretical interest in the transport properties of these systems.The main interest in the study of transport properties of double barrier devices is originated by the possibility of obtaining a region of negative differential resistance in the CurrentVoltage (l--V ) characteristics. For development and interpretation of experimental results of the oscillations in double barrier resonant tunneling structure due to the external time-dependent condition variation, it is necessary that the calculation of the time--dependent Schrodinger equation should be carried out by using suitable approximative method. In this paper, the indirect electron resonant tunneling probability and tunneling current density of the double barrier structure GaAs/AlGaAs are investigated in external time--dependent alternating electric field. Since it is difficult to solve the time-dependent Schrodinger equation without some simplifications,the problem is settled by allowing an external time--dependent alternating electric field as perturbation. Mathematically, the electronic wavefunctions of different space locations are obtained by the use of transfer matrix method. The time-depeneent coefficients of the electronic wavefunctions, which are related to the external condition variation, are obtained by the use of perturded method. Lastly, the resonant tunneling probability and tunneling curreent densiyt are calculated. The results are in qualitative agreement with experiments. The addition oscillation peats in direct tunneling probability curve are connected with the external time--dependent allternating electric field. The additional step in direct tunneling l-V curve can be explained by the use of the calculated results. These results show that coupling of the ectermal alternating electric field and the electroic states with energy E±ω provides indirect channels and paths for tunneling electrons. These methods can be used to study the resonant tunneling of quantum well and quantum wire.
出处
《南京大学学报（自然科学版）》
CSCD
1995年第3期377-382,共6页
Journal of Nanjing University（Natural Science）
