REFRACTIVE-INDEXES OF WURTZITE AND ZINCBLENDE GAN

Refractive index measurements on both wurtzite and zincblende CaN film s grown by plasma-enhanced molecular beam epitaxy are reported. For bi refringent uniaxial wurtzite GaN samples the index of refraction was m easured along the c crystalline axis. In this direction the index is 2 .78 at 3.4eV. For cubic GaN films grown on GaAs substrates, the refrac tive index is 2.91 at 3.2eV. Estimation of the confinement factor for optimised waveguides bawd. a combination of III-V nitrides indicates v ery favourable values for laser operation.