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  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. © 1995 American Institute of Physics.