Abstract

Near-field scanning optical microscopy (NSOM) revealed many important features of semiconductor nanostructures. The unprecedented high spatial resolution of NSOM was achieved recently and a strikingly new feature in the single-dot spectroscopy was reported [1]. Namely, the spatial extent of the luminescence corresponding to the transition from the biexciton state to the exciton state is remarkably narrower than that of the exciton to the ground state transition. This observation was interpreted in terms of the center-of-mass confinement of the biexciton state, namely a kind of the dead-layer model [1]. Although this model gives a qualitative interpretation, a more quantitative theory is necessary to estimate the ratio of the FWHM of the spatial extent of both luminescence patterns and to understand the quantum-dot-size dependence of that ratio. We develop such a theory in the simplest form.

© 2003 Optical Society of America