Izvorni znanstveni članak
Influence of γ-irradiation on optical and electrical properties of amorphous CuInSeTe, CuInSTe and CuInSeS thin films
Laila I. Soliman
; Solid State Physics Laboratory, National Research Centre, Cairo, Egypt
Sažetak
Thin films of quaternary CuInSeTe, CuInSTe and CuInSeS, of thickness 180 nm, were deposited on glass or quartz substrates at 300 K by thermal evaporation under vacuum of 0.13 MPa (10−6 Torr) with a deposition rate of about 6 nm/s. The bulk and thin films of the samples were tested by X-ray diffraction, which revealed that the bulk samples have a polycrystalline structure whereas the thin films are amorphous. The X-ray fluorescence analysis as well as the chemical analysis indicates very slight variations of the film constituents after γ-irradiation. The dependence of the absorption coefficient on photon energy showed the existence of an indirect energy gap in all quaternary films. Moreover, these optical band gaps decreased after increasing the γ-ray doses at room temperature. The validity of the Urbach rule was investigated and the respective parameters were estimated. Resistivity and Hall effect measurements showed that the CuInSeTe, CuInTeS and CuInSeS thin films are p-type semiconductors. The resistivity decreased after increasing the γ-ray doses. The decrease of the values of energy gaps and the resistivity at room temperature of the films with increased γ-ray doses are interpreted in terms of the variation of the density of states model of Mott and Davis, and explained as due to the unsaturation of bonds in amorphous solid.
Ključne riječi
thin films of CuInSeTe; CuInSTe and CuInSeS; amorphous; γ-irradiation; optical band gaps; resistivity; Hall effect; unsaturation of bonds
Hrčak ID:
301576
URI
Datum izdavanja:
1.8.2002.
Posjeta: 159 *