SCANNING TUNNELING MICROSCOPE AND ELECTRON-BEAM-INDUCED LUMINESCENCE IN QUANTUM WIRES

Quantum wire structures of GaAs/A]GaAs have been grown by metalorganic vapor phase epitaxy in V grooves using pre-etched corrugated substrates and have been characterized by high-resolution transmission electron microscopy. Low-temperature cathodoluminescence (CL) identifies luminescence peaks with the spatial distributions of the different recombinations, achieving a top view spatial resolution of almost-equal-to 0.2 mum in the CL images. Principally we report how a scanning tunneling microscope (STM) induces local luminescence in the sample structure, and we spectrally resolve STM-induced luminescence for the tip in different positions relative to the wires. We have recorded the luminescence from a single wire and observed band-filling effects resulting from varying levels of excitation into a wire. We have demonstrated the difference between recombination of electron-hole pairs generated in CL and the recombination of injected holes from the STM tip with a thermalized distribution of accumulated electrons in scanning tunneling luminescence.