Abstract: A quantum-information processing scheme based on electric-field dependent manipulation of spin-information for a shallow hydrogenic impurity is investigated. Calculations for electrical g tensor modulation for a single Silicon donor embedded in a GaAs-substrate is done by extending the effective mass treatment of shallow donors to the 8-band k.p model. The electric-field(E) quenches the donor electron's orbital angular momentum by altering quantum-confinement which modulates the g tensor. The calculated g-factors are highly nonlinear functions of the applied electric and magnetic fields and is unlike that seen in quantum dots. This is attributed to the weaker nature of the confinement potential for a shallow donor atom. The donor electron's spin-dynamics, for the spin-split-1S level, was calculated exactly by using time evolution operators. It is seen that as a consequence of the nonlinear nature of g(E), spin-flip transitions can be made resonantly at subharmonics of the Larmor frequency. Possibilities of using 2D and 1D quantum confinement to obtain more rapid Rabi oscillations is being investigated. I will also briefly discuss some of our work on nanowires, which includes g-factor calculations for nanowhisker-quantum-dots, comparison with experiment and related pseudopotential band structure calculations.