Abstract
We report the molecular beam epitaxial (MBE) growth of high-quality In1-xGaxP epilayers grown on a GaAs (001) substrate using a valved phosphorus cracker cell at a wide range of V/III flux ratios. Film characterization was carried out using X-ray diffraction (XRD), Raman scattering and low-temperature photoluminescence (PL). A typical Raman spectrum showed features characteristic of atomic disorder in the material with the appearance of GaP-like and InP-like longitudinal-optic (LO) modes and the transverse-optic (TO) mode. The PL peak energy increased from 1.941 eV to 1.967 eV while the PL full-width at half maximum (FWHM) decreased from ∼11.3 meV to ∼6.3 meV as the V/III ratio was increased from 5 to 50. This suggests an increase in the atomic disorder (more random) and improvement in the optical quality. The Stokes shift, estimated from the energy difference between the band-gap calculated using XRD composition and PL peak energy, suggests an increase in microclustering following a decrease in the V/III ratio.
Published Version
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