什么是激子波尔半径

Question

什么是激子波尔半径

Answer 1

sarin_2005(站内联系TA)沙发!\x0d不太懂,顶起!顺便学习!victor3828(站内联系TA)我也想知道,帮你顶!ekin007(站内联系TA)It's a vital concept in quantum dots.Hope this description would be helpful:\x0dExciton不用多说了,就是电子空穴对.\x0dExciton Bohr radius is the natural physical separation in a crystal between an electron in the conduction band and the hole it leaves behind in the valence band.The size of this radius controls how large a crystal must be before its energy bands can be treated as continuous.Therefore,the Exciton Bohr Radius can rightly be said to define whether a crystal can be called a semiconductor quantum dot,or simply a bulk semiconductor.(一般的QD的玻尔激子半径大概几个纳米,比如CdSe:4.9 nm; CdS:2.8 nm.)\x0dIn a large semiconductor crystal,the Exciton Bohr Radius is small compared to the crystal,and the exciton is free to wander throughout the crystal.In a quantum dot,the Exciton Bohr Radius is on the order of the physical dimension of the dot or smaller,and the exciton is confined.This second set of conditions is called quantum confinement,which is synonymous with having discrete,rather than continuous energy levels.\x0d注:玻尔半径是以氢原子为模型提出的,因为外层只有一个电子,玻尔半径就定义为从原子核到外面那个电子可以运行的轨道的距离.QD中激子玻尔半径是根据这个引申出来的.\x0d唐小梅(站内联系TA)电子空穴对（激子）看作了一个氢原子模型,电子相对与空穴出现几率最高的位置与\x0d空穴之间的距离就是这种物质的波尔半径