Transmission electron microscopy observation of crystal twinning in periodically inverted AlGaAs grown by low-temperature molecular beam epitaxy

Abstract

We report on the twin structures formed in periodically inverted AlGaAs fabricated by a sublattice-reversal epitaxy technique identified by conventional transmission electron microscopy (TEM). By two-beam-condition TEM and X-ray diffraction analysis, we have confirmed that the twin structures are formed on the (111)A and A planes in both inverted and noninverted domains.

Quasi-phase matched difference frequency generation in corrugation-reduced GaAs/AlGaAs periodically-inverted waveguides

“…We suggest that the large propagation losses for the pump light are dominated by the scattering by the interface corrugations as well as light absorption by the Urbach tail. In addition, the increased loss for the signal light and a part of the loss for the pump in the CMP waveguide is probably due to twin defects 30) which are clearly observed as slanted lines in the CMP waveguide [Fig. 1(b)] whereas no indication of the defect is seen in the non-CMP waveguide [Fig.…”