The use of a surfactant (Sb) to induce triple period ordering in GaInP

A surfactant is used to induce an ordered structure in an epitaxial layer. The addition of small amounts of triethylantimony during the organometallic vapor phase epitaxy growth of GaInP on (001) GaAs substrates is shown to remove CuPt ordering with a resultant increase in band gap energy. Increasing the concentration of Sb in the vapor beyond a critical Sb to P ratio [Sb/P(υ)] of 4×10^-4 gives a reversal of this behavior. The band gap energy is observed to decrease by 50 meV at a concentration of Sb/P(υ) = 1.6×10^-3 coincident with the formation of an ordered phase with a period triple the normal lattice spacing along the [111] and [111] directions. The formation of this new ordered structure is believed to be related to high concentrations of Sb on the surface, which leads to a change in the surface reconstruction from (2×4)-like to (2×3)-like, as indicated by surface photoabsorption performed in situ.