Surface photoabsorption studies of the chemical structure of GaInP grown by organometallic vapor phase epitaxy

Abstract

The surface structure of Ga0.52In0.48P was studied by surface photoabsorption. An absorption peak due to P dimers on Ga0.52In0.48P was observed at ∼400 nm, shorter than for InP (430 nm). From comparison with results for GaAs and InP, the data are interpreted to indicate that at a tertiarybutylphosphine (TBP) pressure of 50 Pa for temperatures below 670 °C, the P-stabilized surface has P dimers aligned along the [1̄10] direction, i.e., it has a (2×4)-like structure. Above 670 °C, the 400 nm peak due to the P-dimer structure disappears because of P desorption from the surface at this TBP partial pressure. Epitaxial Ga0.52In0.48P layers grown using TBP, trimethylgallium and ethyldimethylindium are nearly disordered at 670 °C and highly ordered at 620 °C. These data suggest a correlation between surface structure and ordering.