Determination of Optical, Electrical and Thermal Properties of Gum Arabic Thin Films and its Applications in a Capacitor

Abstract

The aims of this thesis to determination of optical, electrical and thermal properties of Gum Arabic (Hashaba, Talha and Neem) Thin Films and Applied as Capacitor. Thin film from three types of Gum Arabic (Hashaba, Neem and Talha) were synthesized using mechanical method (four thicknesses from each type). FTIR used to determine the bond of three gum types while UV- spectrophotometer used to determine some optical properties and thermal properties were obtained through Forbas’s method. From FTIR results display that all samples of Hashab and Neem have five bonds but Talha has seven bonds. Also reveal that the three types of gum Arabic are similar bonds of (Alkanes, Aromatic and Alkyl halides). UV-VIS results show that the maximal absorbance value equal (0.995 a.u) at wavelengths (257 and 295) nm for Hashaba, but for Neem equal (0.876 a.u) and for Talha equal (1.0029 a.u) at same wavelengths (230 and 287) nm. The value of absorbance increase by increase the thickness of each sample. The maximal value of absorption coefficient (α) for the three types of Gum Arabic (Hashaba, Neem and Talha) equal ( 1.6x108) at different wavelengths (258) nm for Hashaba,(229.7) nm for Neem and 230.46nm forTalha , this means that the transition must corresponding to direct electronic transition.The value of the optical energy gap (Eg) of all samples were increased from (3.925eV) to (4.049eV) due to decreased in thickness of the samples, that means these types of the gum Arabic thin film classified as isolator materials. It was found that the maximum value of refractive index (n) is (1.588) for all Gum Arabic (Hashaba, Neem and Talha) samples at wavelengths ranged (310 to 325) nm. The optical properties used to calculate the electrical properties of these types of the gum Arabic. The maximum value of real dielectric constant (ε1) equal to (19.22) at wavelength 295 nm for the Hashaba Gum Arabic samples, but for the Neem samples equal 7.01 at 288 nm wavelength and for the Talha Gum Arabic samples equal 6.14 at the same wavelength (288 nm).The high magnitude of optical conductivity reached (1.679x1015 sec-1) at wavelengths range (303 to 315) nm. For all samples which confirms the highest photo-response of the twelve samples. The maximum value of electrical conductivity for all samples equal 24.3 (Ω.cm)-1 at wavelengths range (304 to 340) nm. The maximal value of thermal conductivity resaved at the maximal samples thickness (176.6 nm) for all types of gum Arabic, for hashaba equal 190W/ (m. ko), 193.8 W/ (m. Ko) for Neem and 195.7 W/ (m. Ko) for Talha. The capacitor has been Syntheses by using FTO glass and three types of the gum Arabic, the capacitive reactance were calculated as well. The maximum value of capacitive reactance at minimum thickness (14.40 nm) for all samples, for Hashaba equal to 0.308 Ω, for Talha was 0.317 Ω and 0.313 Ω for Neem.