Raman scattering (RS) spectroscopy is employed to characterize the effect of nitrogen on structural properties of GaNxP1-x alloy with nitrogen composition up to 3%. Two-mode behavior of the alloy is clearly shown. The frequency of the GaP-like LO phonons is found to decrease with N composition as -1.13 cm-1 x. This dependence is proposed to be largely due to the biaxial strain in the GaNP epilayers, as a result of lattice mismatch to the GaP substrate. The frequency of the GaN-like phonons is found to be more sensitive to nitrogen content, increasing with the rate of +2.6 cm-1 x. The addition of nitrogen is also found to cause a dramatic quenching of the two-phonon Raman scattering and an appearance of the zone edge GaP-like vibrations. These effects are suggested to reflect local distortion in the GaNP lattice induced by nitrogen, as well as possible clustering of N atoms.
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|Publication status||Published - 2002|