Vibrational Properties Of Gaas0.915n0.085 Under Bydrostatic Pressures Up To 20 Gpa

We investigated a GaAs0.915N0.085 single crystal under hydrostatic pressures LIP to 20 GPa by Raman spectroscopy. The zinc blende optical phonons show great similarities to those of binary GaAs under the same conditions demonstrating that nitrogen incorporation has no major influence on the GaAs-I to GaAs-II phase transition and its partial reversibility upon decompression. Frequency shifts of the nitrogen local vibrational mode under hydrostatic pressure are very different from those in binary GaN because of the different compressibilities of the two materials and the overstretched character of the Ga-N bond in Ga(As,N). This is also reflected by the anharmonicity of the Ga-N bond potential in Ga(As,N).