Ordering in GaInP: Is it relevant for devices?

As many other ternary and quaternary compound semiconductors, GaInP shows natural superlattice ordering consisting of Ga-rich and In-rich (1 1 1) crystal planes which causes a strong change of many material properties. This paper presents three examples how these effects can be used to optimize optoelectronic devices or even to develop new device concepts: (i) The ordering-induced symmetry reduction causes a lifting of the valence-band degeneracy thus enabling the reduction of the threshold current in lasers owing to the reduced density of states. (ii) By ion implantation-induced disordering, we could fabricate lateral order/disorder structures which form the grating of optically pumped distributed feedback lasers. (iii) Due to the drastically anisotropic light propagation properties for optical waveguides parallel to the ordering planes, new waveguide eigennmodes can be designed. Thus we could realize a polarization converter, tunable by an external voltage mainly owing to the Franz-Keldysh effect. However, the domain structure of the ordered material may counterbalance these advantages as explicitly shown on the ordered laser structures. (C) 1998 Elsevier Science B.V. All rights reserved.