The optical properties of multiple nanoscale twin boundaries in indirect-gap AlGaAs epilayers were studied. Twin boundaries of Σ3-type, extended on {111}B, were self-organized in an epilayer during epitaxial growth on an AlGaAs(001) substrate by metal–organic vapor-phase epitaxy. Polarized cathodoluminescence spectroscopy in a transmission electron microscope revealed that a set of parallel twin boundaries arranged at similar intervals of nm-length emitted an intense monochromatic light which was polarized parallel to the boundaries. The photon energy was tunable by controlling the intervals of the boundaries, without changing the crystal structure or the composition.

Intense Monochromatic Light Emission from Multiple Nanoscale Twin Boundaries in Indirect-gap AlGaAs Epilayers. Y.Ohno, N.Yamamoto, K.Shoda, S.Takeda: Japanese Journal of Applied Physics, 2007, 46[35], L830-2