  A variational calculus method is applied for hydrogen-like impurities states
and exciton states in AlGaAs/GaAs quantum wells within the effective masses
approach. The hamiltonian is separated into radial and transversal parts to be
considered and optimized using trial wavefunctions. The results satifsy the
well-known cases of three-dimentional and two-dimentional hydrogen. The donor
and exciton bound energy is shown to decrease while widthening the quantum
well. The non-symmetrical donor position also decreases the bound energy.
