الفهرس 
Theoretical background and literature reviewOnly 14 pages are availabe for public view
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Abstract
Thin films of thallium indium disulfide (TlInS2) are fabricated using thermal evaporator technique onto optical flat glass and quartz substrates. The obtained films are of good homogeneity and adhesion to the substrates. Subsequently, the pristine film is annealed at 423 K and 523 K for 30 min. Energy dispersive X-ray analysis show that TlInS2 consists of Tl (53.31%), In (29.95%) and S2 (16.73) which are nearly stoichiometric. Information on the crystal structure, average particle size, dislocation density and microstrain are obtained for the pristine film as well as the annealed film via conducting XRD. Moreover, the results of XRD are compared to other structural models such W-H and SSP models. The DC electrical conductivity is measured in the temperature range 358 - 473 K. The temperature dependence of TlInS2 thin films confirms the semiconductor nature. Moreover, the activation energy is estimated and found to be 0.97 eV. The frequency and temperature dependence of the AC conductivity σAC, the real part of the dielectric constant, the imaginary part of the dielectric constant, and the dielectric modulus are investigated in the temperature range 358 – 473 K and in the frequency range 0.5 – 200 kHz. The ac conductivity is found to follow Jonscher’s universal power law (σAC ωS). Additionally, the dielectric constants are found to increase by increasing the temperatures which involve distribution of relaxation times. Further, the temperature dependent exponent s outweighs the correlated barrier hopping (CBH) model for conduction mechanism. Studying the real part of the dielectric modulus shows that the disability of driving forces (at low frequencies) which governs the mobility of charge carriers.
The transmittance and the reflectance of the as-deposited and annealed TlInS2 thin films are measured at normal incidence of light using double beam spectrophotometer. Afterwards, the refractive index, extinction coefficient, absorption coefficient are calculated using the absolute values of the transmittance and reflectance. Studies of nanostructured TlIns2 thin films show that these films possess high values of refractive index in the pristine condition as well as the annealed conditions. Also, increasing the value of refractive index all over the spectra because of the annealing temperature can be attributed to the decrease of average particle size. All calculated dispersion parameters namely, the oscillator energy, Eo the dispersion energy, Ed, the high frequency dielectric, ε and the dielectric constant, εL show dependence on the annealing temperatures.