The ion-beam-induced amorphization of crystalline graphite layers was studied by using near-IR visible and near-UV reflectance spectra to obtain the real and imaginary parts of the refractive index as a function of photon energy in the range 0.5-7 eV. In order to obtain an amorphous thickness well above the light beam penetration depth (about 50-100 nm), a 600 keV Kr+ beam was used. In the irradiated graphite the imaginary part of the refractive index below 1 eV shows an evident decrease as for a semiconductor material with an optical pp of 0.5 eV, obtained with the Tauc procedure for the absorption coefficient. The observed metal-to-semiconductor transition was related to the strong bonding rearrangement induced by the heavy ion irradiation on the atomic scale.
OPTICAL-CONSTANTS IN ION-IRRADIATED GRAPHITE
COMPAGNINI, Giuseppe Romano;
1994-01-01
Abstract
The ion-beam-induced amorphization of crystalline graphite layers was studied by using near-IR visible and near-UV reflectance spectra to obtain the real and imaginary parts of the refractive index as a function of photon energy in the range 0.5-7 eV. In order to obtain an amorphous thickness well above the light beam penetration depth (about 50-100 nm), a 600 keV Kr+ beam was used. In the irradiated graphite the imaginary part of the refractive index below 1 eV shows an evident decrease as for a semiconductor material with an optical pp of 0.5 eV, obtained with the Tauc procedure for the absorption coefficient. The observed metal-to-semiconductor transition was related to the strong bonding rearrangement induced by the heavy ion irradiation on the atomic scale.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
