球形GaAs量子点中心类氢杂质基态束缚能的研究

The Ground Binding Energy of a Center Hydrogenic Impurity in Spherical GaAs Quantum Dots

本文运用有限差分方法研究了球形GaAs量子点中类氢杂质基态束缚能。GaAs材料导带底具有抛物特征,电子受限于球形GaAs量子点可以看成是受到抛物势场限制。研究结果表明:球形量子点中类氢杂质基态束缚能与量子点的半径和导带抛物势参数有关。对于小半径量子点,杂质基态束缚能随量子点半径的增加变化明显,当半径增加到一定时,量子点半径的变化对束缚能影响很小,趋于不变的趋势,但是对于大半径的量子点,杂质基态束缚能受抛物势参数的影响很大,这是抛物势场限制宽度与量子点阱宽两个特征长度相互竞争的结果。

The ground binding energy of a hydrogenic impurity in spherical GaAs quantum dots is investi-gated by using finite difference method. The electron bound in GaAs quantum dots can be viewed as a confined parabolic potential to the electron due to the parabolicity in the bottom of the conduction band of GaAs material. The results show that the ground binding energy of a hydrogenic impurity in spherical GaAs quantum dots closely depends on the radius of quantum dot and the parabolic potential parameter related to the conduction band. It is easily found that the ground binding energy of a hydrogenic impurity changes considerably with the increasing of the radius of quantum dot from a small radius. As the radius of quantum dot attains a certain value, the change of the radius of quantum dot has little impact on the ground binding energy of a hydrogenic impurity;however, the parabolic potential parameter can considerably change the ground binding energy of a hydrogenic impurity for a large of radius of quantum dot. This is the result of the coupling and competition between the confining widths of the well potential and parabolic potential.