Elecric field effect on the binding energy of a non-hydrogenic donor mpuirfty in a cylindrical cross-sectional quantum well wire

The effect of an electric field on the non-hydrogenic binding energy of a shallow donor impurity in a cylindrical cross-sectional GaAs-(Ga,Al)As quantum well wire (QWW) was investigated. Within the effective mass approximation, the non-hydrogenic binding energy of the donor impurity was calculated by a variational method as a function of the wire radius, donor impurity position and applied electric field. The results show that the non-hydrogenic binding energy of the donor impurity located around the centre is larger than that of the hydrogenic binding energy. The difference in binding energy of an on-centre shallow donor impurity in the two regimes increases more rapidly with decreasing QWW radius than for other impurity positions. It has been found that the sensitivity of the donor binding energies to the applied electric field in both regimes is almost the same. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.