Time-resolved luminescence of InP quantum dots in aGa0.5In0.5Pmatrix: Carrier injection from the matrix

We conducted time-resolved luminescence spectroscopy on self-assembled InP dots in a ${\mathrm{Ga}}_{0.5}{\mathrm{In}}_{0.5}\mathrm{P}$ matrix at different photon excitation energies. In comparison with results on ${\mathrm{Ga}}_{0.5}{\mathrm{In}}_{0.5}\mathrm{P}$ without dots, the influence of the ${\mathrm{Ga}}_{0.5}{\mathrm{In}}_{0.5}\mathrm{P}$ matrix on luminescence-decay profiles of InP dots was clarified. By excitation at the ${\mathrm{Ga}}_{0.5}{\mathrm{In}}_{0.5}\mathrm{P}$ matrix, the long-decay component $\left(\sim 50\mathrm{n}\mathrm{s}\right)$, as well as the 400 ps radiative-decay component, was observed in luminescence of InP dots. This long-decay component reflects carrier lifetime in the ${\mathrm{Ga}}_{0.5}{\mathrm{In}}_{0.5}\mathrm{P}$ matrix. Carrier injection time from the ${\mathrm{Ga}}_{0.5}{\mathrm{In}}_{0.5}\mathrm{P}$ matrix to InP dots is estimated to be $\sim 100$ ps, and is determined by carrier diffusion in the matrix.