Effect of substrate temperature on the properties of vacuum evaporated indium selenide thin films

✍ Scribed by C. Viswanathan; V. Senthilkumar; R. Sriranjini; D. Mangalaraj; Sa. K. Narayandass; Junsin Yi

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 236 KB
• Volume: 40
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.200410404

✦ Synopsis

Thin films of InSe were obtained by thermal evaporation techniques on glass substrates maintained at various temperatures (T sb = 30°, 400°C). X-ray diffraction analysis showed the occurrence of amorphous to polycrystalline transformation in the films deposited at higher substrate temperature (400°C). The polycrystalline films were found to have a hexagonal lattice. Compositions of these films have been characterized by EDAX and the surface analysis by scanning electron microscopy. Optical properties of the films, investigated by using spectrophotometer transmittance spectra in the wavelength range (300 -1100 nm), were explained in terms of substrate temperatures. Films formed at room temperature showed an optical band gap (E g opt ) 1.56 eV; where as the films formed at 400°C were found to have a E g opt of 1.92 eV. The increase in the value of E g opt with T sb treatment is interpreted in terms of the density of states model as proposed by Mott and Davis. The analysis of current -Voltage characteristics, based on space charge limited currents (SCLC) measurements, confirms the exponential decrease of density of states from the conduction band edge towards the Fermi level for both the amorphous and polycrystalline films.