METALORGANIC VAPOR-PHASE EPITAXY GROWTH AND CHARACTERIZATION OF (ALXGA1-X)0.5IN0.5P/GA0.5IN0.5P (X=0.4, 0.7 AND 1.0) QUANTUM-WELLS ON 15-DEGREES-OFF-(100) GAAS SUBSTRATES AT HIGH GROWTH-RATE

High-quality bulk layers of (AlxGa1-x)0.5In0.5P (=0 to 1.0) and (AlxGa1-x)0.5In0.5P/Ga0.5In0.5P (x=0.4, 0.7 and 1.0) quantum wells (QWs) have been grown on 2-degrees- and 15-degrees-off-(100) GaAs substrates by means of low-pressure metalorganic vapor phase epitaxy at a high growth rate of 9 angstrom/s. The high-resolution transmission electron microscopic (TEM) image indicates the interfacial abruptness to be on the order of one monolayer. Photoluminescence (PL) results indicate an increase in peak energy and a decrease in full width at half-maximum (FWHM) for samples grown on 15-degrees-off substrates, due to the suppression of sublattice ordering. For QWs with a direct barrier, an intense and distinct PL peak can be clearly observed for well thickness as thin as 9 angstrom. However, no emission is observed for the 9 angstrom well in the Al0.5In0.5P/Ga0.5In0.5P QWs, due to the indirect transition from the X-valley in AlInP to the heavy hole valence band of GaInP. For the first time, (Al0.7Ga0.3)0.5In0.5P/Ga0.5In0.5P multiple quantum wells (MQWs) with well widths of 9 angstrom have been obtained. The 20 K PL peak energy corresponds to a wavelength of 545 nm, the shortest ever reported for (AlxGa1-x)0.5In0.5P/Ga0.5In0.5 P MQWs.