ANALYSIS OF ORDERING IN GAINP BY MEANS OF X-RAY-DIFFRACTION

Ga0.51In0.49P layers grown by metal-organic vapor-phase epitaxy in the temperature range from 600 to 730-degrees-C and with various Si-doping concentrations were studied. X-ray diffraction was used to observe the ordering in Ga0.51In0.49P layers. The rocking curves of {115} reflection have shown the existence of ordering in Ga0.51In0.49P even in Si-doped samples with an electron concentration up to 1 x 10(19) cm-3. The samples with ordered structure exhibit an additional {1/2, 1/2, 5/2} reflection. However, no such reflection, which is related to group-III sublattice ordering, was observed in GaAs, AlGaAs, and GaInP layers grown at 730-degrees-C. Photoluminescence (PL) and transmission electron diffraction (TED) results confirm these observations. TED patterns and especially the intensity of the additional ordering spots of Ga0.51In0.49P samples are almost unchanged in the studied doping range up to 1.7 x 10(18) cm-3. An increase of PL peak energy attributed to the ordered structure randomization was not observed. The PL peak shift for highly doped Ga0.51In0.49P was found to be only due to the Burstein-Moss effect.