Unusual properties of photoluminescence from partially ordered Ga_0.5In_0.5P

Ga_0.5In_0.5P grown lattice matched to GaAs by metalorganic chemical vapor deposition (MOCVD) exhibited domains of varying degrees of column III sublattice ordering. Continuous‐wave photoluminescence spectra were single peaked and relatively narrow, but the peak wavelengths from samples grown at low (630–670 °C) temperatures varied strongly with excitation density at low measurement temperatures, while peak wavelength did not vary for high (775 °C) temperature growth. The half width was 6.5 meV in the latter case, the narrowest reported from MOCVD‐grown Ga_0.5In_0.5P. Time‐resolved photoluminescence of partially ordered GaInP at liquid‐helium temperatures is reported for the first time. For samples grown at low temperatures, the spectral peak displayed a slow (τ≳1 μs) decay at low excitation density. The decay was more rapid (τ=1.8 ns) at higher excitations and at higher photon emission energies. Possible explanations discussed include spatial separation of carriers and trapping.<squeeze;1.6p>