Raman scattering characterization of Si-doped Ga0.52In0.48P grown by solid source molecular beam epitaxy

The effect of silicon (Si) doping on Ga0.52In0.48P epitaxial layers grown by solid source molecular beam epitaxy (SSMBE) using the valved phosphorus cracker cell has been studied using Raman spectroscopy. The Raman spectrum of the undoped sample show a modified two-mode behavior with clear existence of the GaP-like and InP-like longitudinal optical (LO) phonons, and the InP-like transverse optical (TO) phonons. Two plasmon-LO-phonon modes (L+ and L−) were observed in the spectra of the doped samples, and their frequencies were dependent on the electron concentration. There is evidence to suggest that increase in the electron concentration result in an increase in the level of ordering in the material. The two-mode (L+ and L−) behavior was found to fit the effective mass values of the conduction band more appropriately compared to the one-mode (L+) behavior in the case of our SSMBE-grown Si-doped GaInP samples.