https://doi.org/10.1051/epjap:2000158
Optical properties of CdI2 thin films
Physics Department, Faculty of Education, Ain Shams University, Cairo, Egypt
Corresponding author: ashraf.bekheet@mailcity.com
Received:
12
November
1999
Revised:
26
June
2000
Accepted:
26
June
2000
Published online: 15 September 2000
The transmittance (T) of thin films of CdI2, prepared by thermal evaporation technique on quartz substrates, have been measured over the wavelength range 200−900 nm. From analysis of the transmittance data, the optical constants, the refractive index (n) and the extinction coefficient (k), have been studied. Analysis of the refractive index (n) yields a low frequency dielectric constant, average oscillator strength and average oscillator energy. From analysis of the absorption coefficient (α), the fundamental absorption edge can be determined. Both allowed direct transitions and allowed indirect transitions are observed. The composition of films is checked using energy dispersive X-ray (EDX) spectroscopy technique. X-ray diffraction (XRD) measurements showed that the CdI2 films evaporated at room temperature substrates were characterized by a polycrystalline form. At large thicknesses the films indicated the inhomogeneity. The effect of annealing temperature (up to 523 K) on the film properties has been studied.
PACS: 78.20.-e – Optical properties of bulk materials and thin films / 78.20.Ci – Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) / 78.66.Li – Other semiconductors
© EDP Sciences, 2000
