Tuning the binding energy of surface impurities in cylindrical GaAs/AlGaAs quantum dots by a tilted magnetic field

Using the potential morphing method in the framework of the effective-mass approximation, we have studied theoretically the effect of a tilted magnetic field on the binding energy of surface impurities in GaAs/Al0.3Ga0.7As cylindrical quantum dots. It is found that contrary to what was expected based on the existing literature for growth-direction magnetic fields, the presence of a tilted field does not always contribute positively to the binding energy of surface impurities. The shape (aspect ratio) and size of the cylindrical QD as well as the dopant positions at the QD surface play an important role. Furthermore, we find that decrease of the QD size can reduce the sensitivity of the variation of the donor binding energy with respect to the field strength (orientation), but it cannot change its general behaviour. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4754824]