We have calculated variationally the ground state binding energy of a hydrogenic donor impurity in V-shaped quantum well (VQW) or full-graded GaAs/Ga1-xAlxAs quantum wells in the presence of crossed electric and magnetic fields. These homogeneous crossed fields are such that the magnetic field is parallel to the heterostructure layers and the electric field is applied perpendicular to the magnetic field. The dependence of the donor impurity binding energy on the well width and the strength of the electric and magnetic fields are discussed. We hope that obtained results will provide important improvements in device applications, especially for narrow well widths and for a suitable choice of both fields. (c) 2004 Elsevier B.V. All rights reserved.