Zhu, Q. and Pelucchi, E. and Dalessi, S. and Leifer, K. and Dupertuis, M. A. and Kapon, E.

2006

Nano Letters

Alloy segregation, quantum confinement, and carrier capture in self-ordered pyramidal quantum wires

Validated

()

6

5

The structure and photoluminescence (PL) characteristics of AlGaAs quantum wires self-formed by metallorganic vapor-phase epitaxy in inverted tetrahedral pyramids are reported. Capillarity-driven Ga-Al segregation yields vertical quantum wires (VQWRs) at the center of the pyramid, connected to more-weakly segregated vertical quantum wells ( VQWs) formed along their wedges. The segregation is evidenced in transmission electron microscope images and in the PL spectra of these structures. Transitions between quantum-confined electron and hole states in the VQWR are identified in the micro-PL spectra with energies in good agreement with model calculations. The temperature dependence of the micro-PL spectra clearly reveals efficient carrier capture into the VQWR from the VQWs, particularly at an intermediate temperature range (similar to 100 K) where carrier mobility is enhanced. These wires offer new possibilities for tailoring the confinement potential in one-dimensional systems.