Carrier lifetime in deep-etched ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As/InP quantum wires

We have investigated the influence of nonradiative sidewall recombination on the carrier dynamics in deep-etched ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As/InP quantum wires by time-resolved photoluminescence spectroscopy using optical up conversion. Down to wire widths of about 50 nm we observe only a weak decrease of the carrier lifetime with decreasing wire width due to nonradiative recombination processes at the wire surfaces. In contrast, the lifetime decreases rapidly for wire widths between 50 and 20 nm. Our results indicate that the surface recombination is not dominated by diffusive carrier transport to the wire surfaces, since the widths of the present wire structures are smaller than the diffusion length of the carriers. Instead, by using a simple model based on the spatial probability distribution of the carriers in the vicinity of nonradiative recombination centers at the wire surfaces, the observed wire-width dependence of the carrier lifetime can be well understood.