NEAR-FIELD OPTICAL SPECTROSCOPY OF SEMICONDUCTOR QUANTUM WIRES

We discuss low temperature near-field scanning optical spectroscopical studies of single, nanometer dimension, cleaved edge overgrown quantu m wires. We use the enhanced spatial resolution of near-field microsco py, to spectroscopically investigate these single wires, which are ina ccessible to conventional far-field optical spectroscopy, We thus perf ormed a direct experimental comparison between a two-dimensional quant um system and a single genuine one-dimensional quantum system. We show that the photoluminescence of a single quantum wire is easily disting uished from that of the surrounding quantum well. Emission from locali zed centers is shown to dominate the photoluminescence from both wires and wells at low temperatures. A factor of three enhancement in the o ptical absorption of a wire, in comparison with that of a similar well , is concluded from the photoluminescence excitation data.