  Polarization effects are included exactly in a model for a quantum dot in
close proximity to a planar interface. Efficient incorporation of this
potential into the Schr\"{o}dinger equation is utilized to map out the
influence of the image potential effects on carrier tunneling in such
heterostructures. In particular, the interplay between carrier mass and the
dielectric constants of a quantum dot, its surrounding matrix, and the
electrode is studied. We find that the polarizability of the planar electrode
structure can significantly increase the tunneling rates for heavier carriers,
potentially resulting in a qualitative change in the dependence of tunneling
rate on mass. Our method for treating polarization can be generalized to the
screening of two particle interactions, and can thus be applied to calculations
such as exciton dissociation and the Coulomb blockade. In contrast to tunneling
via intermediate surface localized states of the quantum dot, our work
identifies the parameter space over which volume states undergo significant
modification in their tunneling characteristics.
