ATMOSPHERIC-PRESSURE ORGANOMETALLIC VAPOR-PHASE EPITAXIAL-GROWTH OF (ALXGA1-X)0.51IN0.49P (X FROM 0 TO 1) USING TRIMETHYLALKYLS

(AlxGa1-x)0.51In0.49P layers, lattice matched to (001)-oriented GaAs substrates, have been grown throughout the entire aluminum composition range from x=0 to 1.0 by atmospheric pressure organometallic vapor-phase epitaxy (OMVPE), using trimethylaluminum (TMAl), trimethylgallium (TMGa), trimethylindium (TMln), and phosphine (PH3) as source materials in a horizontal reactor. The growth temperature was held constant at 680 °C. Excellent surface morphologies were obtained over the entire composition range. Unlike previously reported results, neither high growth temperatures nor low pressures were needed in order to obtain good-quality, high-x (AlxGa1-x)0.51In 0.49P alloys using trimethylalkyls. Photoluminescence (PL) was observed, even at 300 K, for all samples with Al solid compositions of x≤0.52. The results show that the energy band gap measured by PL at room temperature for this material varies as Eg=1.9 +0.6x, in accord with previous studies. It was found that the PL emission intensity was nearly constant at 10 K with increasing x in the range from 0 to 0.52. This contrasts with earlier published results which showed a decreasing PL intensity for the higher values of x. The 300-K PL intensity was almost a constant for x≤0.3 and gradually decreased with increasing Al content for x>0.30. The dependence is nearly that predicted from a simple calculation based on the relative occupancies of the Γ and X conduction bands using a constant minority-carrier lifetime. The PL full width at half maximum (FWHM) for x=0 was 7.2 meV at 10 K and 35 meV at 300 K. These are the narrowest reported results to date. For x=0.48, the FWHM was 31 meV at 10 K and 78 meV at 300 K. It was observed that at both 10 and 300 K, the FWHM increased slowly with increasing aluminum concentration.