HOMOGENEOUS LINEWIDTHS IN THE OPTICAL-SPECTRUM OF A SINGLE GALLIUM-ARSENIDE QUANTUM DOT

The homogeneous linewidths in the photoluminescence excitation spectru m of a single, naturally formed gallium arsenide (GaAs) quantum dot ha ve been measured with high spatial and spectral resolution. The energi es and linewidths of the homogeneous spectrum provide a new perspectiv e on the dephasing dynamics of the exciton in a quantum-confined, soli d-state system. The origins of the linewidths are discussed in terms o f the dynamics of the exciton in zero dimensions, in particular, in te rms of lifetime broadening through the emission or absorption of phono ns and photons.