0000000000382947
AUTHOR
R. Pokulis
PHOTOINDUCED HARDENING AND REDUCTION OF DISLOCATION MOBILITY IN C60SINGLE CRYSTALS: THE WAVELENGTH DEPENDENCE
An increase of the microhardness and decrease of the dislocation mobility in C60 single crystals after light-irradiation in the wavelength range of 150–900nm in air has been observed giving evidence for photo-induced change in bonding. Efficiency of C60 phototransformation was found to increase with decreasing the wavelength.
Polymerization and Damage of C60 Single Crystals under Low Fluency Laser Irradiation
Photo-induced hardening, substructure formation and damage of C 60 single crystals under the 632.8 nm He-Ne laser irradiation in air at a power density of 1.47 mW/mm 2 was investigated by microhardness and AFM methods. Photo-induced formation of the dislocation substructure and crystallographically oriented crack patterns on the (111) face due to lattice contraction on polymerization were observed. Two phototransformed states: soft (400-450 MPa) and hard (650-1000 MPa) are found to appear under laser-irradiation. Hard fullerite is created in the subsurface layer < 1 μm at the saturation stage of phototransformation. It softens to 400-450 MPa at 340 K and reverts to non-polymerized state at …
<title>Effect of light exposure on dislocation mobility in fullerite C60 crystals</title>
The illumination-time evolution and the wavelength dependence of the photoinduced changes in dislocation mobility on the (111) face of C60 single crystals in air for the wavelength range 150 - 900 nm and power densities 0.2 - 2 mW/cm2 has been investigated. The results show that the light exposure in air leads to the decrease of the dislocation mobility. The magnitude of the effect as a function of the illumination time was investigated and a two-stage relationship was obtained. The ultraviolet light was found to be more effective than the visible light in the photoinduced reduction of dislocation mobility and solubility. In the wavelength range of 150 - 700 nm, the reduction of dislocation…
<title>Indentation creep and stress relaxation in amorphous As-S-Se and As-S films</title>
The indentation creep in as-deposited and photopolymerized As- S-Se and As-S films has been investigated. The results show pronounced relaxation of mechanical stresses in the films at room temperature. The relationship (sigma) equals B (epsilon) m between the deformation rate and the stress is observed and the values of the deformation rate sensitivity exponent m < 1 are found. The creep rate was found to be dependent on deposition conditions of layers, applied indentation load, structural state of the material and light irradiation during the creep test.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.