用投掷法和有限元差分法计算了单周期调制掺杂GaAs/AlGaAs双量子阱的能带结 构,得到基态能级与第一激发态的能级差为 43.3 meV,并由此推算得到产生载流子横向转 移效应的电场强度为1.2~1.8 kV/cm之间.采用 MBE 技术生长了所涉及的双量子阱结构, 通过优化退火条件,获得了较理想的金属—半导体接触条件.在此基础上,测得在电场强度 为 1.5 kV/cm时,电流—电压曲线呈现出负阻特性.该电场强度区别于GaAs耿氏效应的电 场强度,由此判定,产生微分负阻的机理是电子由高迁移率导电层到低迁移率导电层的横向 转移所致,即实空间转移.

The band structure of a GaAs/AlGaAs double quantum well was calculated via shooting method and finite element method. The energy needed for a ground-excited state transition is 43.3 meV, indicating that a 1.2 to 1.8 kV/cm electric field can cause a horizontal transfer of carriers. The designed double quantum well structure was grown by MBE. Good metal-semiconductor contact was obtained via optimizing annealing conditions. The negative resistance effect was obtained in a 1.5 kV/cm parallel electric field, which is differs from the electric field for GaAs Gunn effect. It was concluded that the mechanism for negative resistance effect is electrons transfer from high mobility layer to low mobility layer, namely real space transfer(RST).