Abstract

The material system (Al) GaInP is very interesting for opto-electronic devices in the visible spectral range. Under suitable growth conditions (Al)GaInP epitaxial layers show a spontaneous self ordering of the CuPt_B-type [1]. For growth in the [100]-direction this ordering results in alternating Ga-rich and In-rich {111}_B planes. The mono-atomic superlattice causes significant changes of the electronic structure compared to the normal disordered alloy. In particular, ordered crystals exhibit a band gap reduction and a valence band splitting at the T-point. As a consequence of dipole selection rules, transitions between the highest valence band and the conduction band are forbidden for light polarized parallel to the ordering direction. This leads to a strong polarization anisotropy even for light propagating normal to the {100} crystal surface.

© 1998 IEEE