  Ag nanoparticles in the form of colloids and ordered arrays are used to
demonstrate plasmon-mediated non-radiative energy transfer from quantum dots to
quantum wells with varying top barrier thicknesses. Plasmon-mediated energy
transfer efficiencies of up to ~25% are observed with the Ag colloids. The
distance dependence of the plasmon-mediated energy transfer is found to follow
the same d^{-4} dependence as the direct quantum dot to quantum well energy
transfer. There is also evidence for an increase in the characteristic distance
of the interaction, thus indicating that it follows a F\"orster-like model with
the Ag nanoparticle-quantum dot acting as an enhanced donor dipole. Ordered Ag
nanoparticle arrays display plasmon-mediated energy transfer efficiencies up to
~21%. To explore the tunability of the array system, two arrays with different
geometries are presented. It is demonstrated that changing the geometry of the
array allows a transition from overall quenching of the acceptor quantum well
emission to enhancement, as well as control of the competition between the
quantum dot donor quenching and energy transfer rates.
