Structural and Optical Properties of Germanium Thin Films Prepared by the Vacuum Evaporation Technique

Germanium (Ge) thin films have been deposited onto the glass substrates by the vacuum evaporation technique. The effect of annealing temperature on the structural and optical properties of the germanium thin films was investigated. The structural and optical properties of thin films were characteriz...

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Bibliographic Details
Published in:Physics research international 2014, Vol.2014, p.1-7
Main Authors: Al-Sharafi, Z., Mohyeddine, S., Osman Mohammed, Samir, Kershi, R. M.
Format: Article
Language:English
Subjects:
Annealing
Crystal structure
Deposition
Electron transitions
Glass substrates
Mathematical analysis
Optical properties
Semiconductors
Spectra
Temperature
Thin films
Vacuum evaporation
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Summary:Germanium (Ge) thin films have been deposited onto the glass substrates by the vacuum evaporation technique. The effect of annealing temperature on the structural and optical properties of the germanium thin films was investigated. The structural and optical properties of thin films were characterized by XRD, SEM, and UV-Vis techniques. XRD results showed that the structure of the deposited thin films changed from amorphous phase for the films, which deposited at room temperature, to crystalline phase for the films, which deposited at high temperature. Optimum temperature to obtain a good crystalline structure was 525°C. The SEM image also showed that the crystallization of the thin films is increased with increasing of annealing temperature. Transmittance and reflectance spectral were used to calculate the absorption coefficient. Two absorption edges in two spectral regions were distinguished according to direct and indirect electron transitions. Energy band gap E g was calculated by using the Tauc relationship for both direct and indirect electron transitions. The average value of E g was equal to 0.79 eV and 0.61 eV for direct and indirect transitions, respectively.
ISSN:2090-2220
2090-2239
DOI:10.1155/2014/594968