Optical Absorption and Structural Properties of as-deposited and Thermally Annealed As-Te-Ga Thin Films | ||||
| Egyptian Journal of Solids | ||||
| Article 4, Volume 25, Issue 1, 2002, Page 33-47 PDF (352.55 K) | ||||
| DOI: 10.21608/ejs.2002.150461 | ||||
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| Abstract | ||||
| Thin films of As30 Te70-x Gax, where x = 0.5, 1, 3, 6 and 10 are deposited on glass substrates by vacuum evaporation. The transmittance and absorbance of the as-deposited films were measured in the spectral range 400-1100nm. The dependence of the absorption coefficient on the photon energy is well described by the relation αhν= B (hν-E0)2. The optical energy is nearly independent on the Ga content up to 3 at.% , then increases continuously from 0.73 eV to 0.9eV with increasing the Ga content. Thermal annealing below and above the glass transition temperature slightly increase and decrease the value of the optical energy gap, respectively. XRD, SAED, TEM and DSC were used to study the structure of the as-deposited and annealed films. The amount and type of the separated polycrystalline phases depend on the original composition of the film and on the annealing temperature. | ||||
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