No abstract

No abstract

Nondoped and (Al, Sb)-doped CdTe thin films with 0.5, 1.5, and 2.5  wt.%, respectively, were deposited by thermal evaporation technique under vacuum onto Corning 7059 glass at substrate temperatures () of room temperature (RT) and 423 K. The optical properties of deposited CdTe films such as band gap, refractive index (n), extinction coefficient (), and dielectric coefficients were investigated as function of Al and Sb wt.% doping, respectively. The results showed that films have direct optical transition. Increasing and the wt.% of both types of dopant, the band gap decrease but the optical is constant asn, and real and imaginary parts of the dielectric coefficient increase.

No abstract

ABSTRACT:In this work, optical properties for thin doped ZnO films , prepared by pulse laser deposition (PLD) technique have been investigated as a function of various Ti concentrations( 0, 2, 4, 6, 8 and10) wt %. This study shows that the films have energy gap decreases from 3.3 eV to 2.4eVwith increasing Ti concentration from 0 to 10 wt%. The optical constants which are refractive index, extinction coefficient, real and imaginary constants were varied upon doping ZnO thin films with different Ti concentrations.

No abstract

Films of CdTe pure and doped with various atomic percentages of Al and Sb (0.5, 1.5 & 2.5) were prepared, and their electrical properties were investigated. The films were prepared by thermal evaporation on glass substrates at two substrate temperatures (Ts=RT& 423 K). The results showed that the conduction phenomena of all the investigated CdTe thin films on glass substrates are caused by two distinct mechanisms. Room temperature DC conductivity increases by a factor of four for undoped CdTe thin films asTsincreases and by 1-2 orders of magnitude with increasing dopant percentage of Al and Sb. In general, films doped with Sb are more efficient than Al-doped films. The activation energy (Ea2) decreases with increasingTsand dopant percentage for both Al and Sb. Undoped CdTe films deposited at RT are p-type convert to n-type with increasingTsand upon doping with Al at more than 0.5%. The carrier concentration decreases asTsincreases while it increases with increasing dopant percentage. Hall mobility decreases more than three times as Al increases whereas it increases about one order of magnitude with increasing Sb percentage in CdTe thin films deposited at 423 K and RT, respectively.

Mannich bases derivatives of Benzimidazole were prepared from condensation reaction of 2mercaptobenzimidazole with formaldeyhed once with mropholine and another with pyrazinamide to prepare L 1 and L 2 respectively, coordinated with three metal ions of Pd(II), Pt(IV) and Au(III). The structures of these compounds were confirmed by metal and elemental analyses, UV-Vis and FT-IR spectroscopy, magnetic susceptibility, conductivity measurement at room temperature, 1 HNMR and 13 CNMR. Experimental results showed that the ligands (L 1 &L 2 ) coordinated as bi-dentate and tridentate with metal ions respectively. Cytotoxicity of Mannich bases and their metal complexes were examined against mice cell line RAW 264.7 using MTT method .Each cell line was injected by following doses (400,200,100 and 50) µg/ml of prepared compounds by using mice cell as a negative control and cis-platin as a positive control. The ligands and Pd(II), Pt(IV), Au(III) complexes showed good activity at various concentrations especially Pd(II) complexes of both complexes.