Elasto-optical properties of zinc-blende (cubic) GaN measured by picosecond acoustics

Using the technique of picosecond acoustics, we measure the basic elastic and optical properties of a micrometre-thickness zinc-blende (cubic) GaN epitaxial film grown on GaAs. We provide low temperature values of the speed of sound, c(11) elastic constant and refractive index. Our value of the elastic constant is in good agreement with the theoretical calculations for cubic GaN (Wright 1997 J. Appl. Phys. 82 2833).