We report on the decay dynamics of positively charged excitons confined to single InAs quantum dots embedded in an n-type field-effect structure. The positively charged exciton's dynamics are found to be strongly dependent on device dimensions. With a large (small) dot capping layer the decay is dominated by hole tunneling (radiative recombination). The hole tunneling is successfully modeled with a WKB-like zero-dimensional to three-dimensional tunneling approximation. Hole tunneling is not observed in the dynamics of the neutral exciton negatively charged exciton, or biexciton, an effect we attribute to an increase in barrier height through the interdot Coulomb interactions. © 2006 American Institute of Physics.