隔离层厚度对量子垒堆结构的电子滤波作用的影响

EFFECTS OF SPACER THICKNESS ON THE ELECTRON FILTING FUNCTION OF QUANTUM BARRIER-STACK STRUCTURES

研究了隔离层厚区对量子垒堆结构的电子滤波作用的影响．对于单隔离层，在较为一般的情况下解析推得隔离层厚度满足的广义Ｂｒａｇｇ公式，以多重双势垒结构为例对多隔离层的情况也进行了研究。结果表明同时存在两类共振隧穿（ＲＴ），第一类ＲＴ是法布里－珀罗型ＲＴ，要求隔离层厚度满足Ｂｒａｇｇ公式或广义Ｂｒｅｇｇ公式；第二类ＲＴ是依次型ＲＴ，对隔离层厚度没有要求．特别指出ｘ＝０的ＲＴ能对于中心对称结构是实现依次型ＲＴ的重要途径．

The effects of spaeer thickness on the electron filting funetion of quantum barrier-stack structures are studied. For the case of single spacer.the generallzed Bragg for mula confining the spacer thickness is derived analytically.The multiple double-barrier structures are also studied as an example of the systems with more than one spacers. The results show that there exist two types of resonant tunneling(RT),one is Fabry-Perot RT. in which the spacer thickness must he satisfied with the Bragg formula or the generallzed Bragg formula; and the another type is the successive RT.in which the spacer thickness has nothing to do with the RT. It is pointed out especially that the RT energies satisfying the equation x= 0 is an important approach to realze successive RT for the systems with central symmetry.