Effect of growth rate on the band gap of Ga_0.5In_0.5P

The band gap of Ga_0.5In_0.5P is reported as a function of growth rate and growth temperature. The Ga_0.5In_0.5P is grown lattice matched to 2°‐off (100) GaAs substrates by atmospheric pressure organometallic chemical vapor deposition using an inlet group V/III ratio of 65. The variation of the band gap is surprisingly complex, taking five different functional forms within the two‐dimensional parameter space. These include regions in which the band gap (1) increases with growth rate, (2) decreases with growth rate, (3) is independent of both growth rate and temperature, (4) is independent of growth rate, but dependent on growth temperature, and (5) is not measurable since three‐dimensional, instead of two‐dimensional, growth is observed. The behavior can only be explained by a theory involving competing processes. One such theory is described.