Crystalline to amorphous transformation in GaAs during Kr ion bombardment: A study of elastic behavior

Abstract
A marked softening in the shear elastic properties of GaAs following 1.5-MeV Kr ion irradiation is observed. Ion channeling and Raman scattering are used to monitor the accumulation of damage, which for 1.5-MeV incident energy extends to a depth of ∼8000 Å. Both techniques show that the sample is amorphized by a dose of 2×1014 ions/cm2. Brillouin scattering reveals that a shear elastic modulus of this near-surface irradiated region decreases by 43% as the material transforms from crystalline to amorphous. The observed results are discussed and compared with similar measurements on Si and intermetallic compounds.