Time dependent surfactant effects on growth of GaInP heterostructures by organometallic vapor phase epitaxy

It has been shown that adding the surfactant Sb during growth eliminates ordering in GaInP by destroying the P dimers on the reconstructed surface. Consequently, the understanding of ordering can provide fundamental information about the surface during growth. This paper reports on the use of the surfactant Sb to modulate the order parameter of GaInP to produce disorder-on-order-on-disorder (D/O/D) heterostructures. It was found that heterostructures grown without interruptions have graded interfaces, but heterostructures grown with interruptions have abrupt interfaces. Secondary-ion mass spectroscopy (SIMS) measurements on the heterostructure grown without interruptions indirectly suggests that the Sb surface concentration changed significantly during growth as triethylantimony was added and removed from the system. Consequently, time dependent surface photoabsorption (SPA) measurements were made to determine the change in the P dimer concentration with the addition of triethylantimony. Comparison of the transient time constants with the Langmuir model suggests that relatively high concentrations of Sb accumulate on the surface during growth of the disordered layers. In addition, the results suggest that a critical concentration of Sb on the surface is necessary before the material disorders. Using the surfactant Sb with interruption results in a powerful tool for controlling the surface during growth. This technique was used to produce a GaInP D/O/D heterostructure with a very thin (67 Å) ordered layer, sharp interfaces and good photoluminescence. The ability of this tool to produce advanced quantum well devices appears feasible.