Studies on the structural, morphological and optoelectrical properties of spray deposited CdS:Pb thin films

AbstractUndoped and Pb-doped CdS (CdS:Pb) thin films were prepared on glass substrates by a spray technique using a perfume atomizer. The effects of Pb doping on the structural, morphological and optoelectrical properties of CdS thin films were studied. All of the films are polycrystalline in nature exhibiting hexagonal crystal structure. Crystallite size estimated from the Scherrer formula increased from 18.42 nm to 34.76 nm with increases in Pb doping concentration. The expansion of lattice parameters experienced with Pb doping might be due to the larger ionic radius of Pb2+ ions compared to that of the host Cd2+ ions. Increased optical transparency is observed for the doped films and the optical band gap experienced band bowing with increase in Pb doping concentration. Electrical resistivity values of the films were found to be on the order of 101 Ω cm. From the obtained results, it is observed that the CdS thin film coated with 6 wt.% Pb doping concentration exhibit better structural, morphological, optical and electrical properties

Characteristic analysis on the physical properties of nanostructured Mg-doped CdO thin films—Doping concentration effect

Highly conductive and transparent magnesium-doped cadmium oxide (CdO:Mg) thin films have been deposited on suitably cleaned glass substrates maintained at 375 °C by spray pyrolysis technique using perfume atomizer. The magnesium content in the films is varied from 0 to 8 at% in steps of 2 at%. The effect of Mg doping on the structural, morphological, optical and electrical properties of the CdO thin films has been studied. All the films exhibited cubic structure with a preferential orientation along the (1 1 1) plane irrespective of the Mg doping level. SEM analysis showed that the film morphology modifies from spherical shaped grains to closely packed cauliflower shaped nanostructures with Mg doping. Except for the film coated with 2 at% Mg dopant, all the other doped films exhibited a blue shift in the optical band gap. Electrical studies revealed that the CdO:Mg film coated with 8 at% Mg dopant had a minimum resistivity of 0.0853×101 Ω-cm

Effect of chlorine doping on the structural, morphological, optical and electrical properties of spray deposited CdS thin films

CdS and chlorine doped CdS (CdS:Cl) thin films with different Cl-doping levels (0, 2, 4, 6 and 8 at%) have been deposited on glass substrates by a spray pyrolysis technique using a perfume atomizer. The effect of Cl doping on the structural, morphological, optical and electrical properties of the films was investigated. XRD patterns revealed that all the films exhibit hexagonal crystal structure with a preferential orientation along the (0 0 2) plane irrespective of the Cl doping level. The particle size value decreases from 22.03 nm to 18.12 nm with increase in Cl concentration. Optical band gap is blue-shifted from 2.48 eV to 2.73 eV with increase in Cl doping concentration. All the films have resistivity in the order of 104 Ω cm. The obtained results confirm that chlorine as an anionic dopant material can enhance the physical properties of CdS thin films to a large extent

Structural, optical, electrical and morphological properties of ZnTe films deposited by electron beam evaporation

ZnTe films were deposited on glass substrates at different substrate temperatures in the range 30–300 �C. The thickness of the films was about 200 nm. The films exhibited cubic structure with preferential orientation in the (111) direction. Band gap values in the range 2.34–2.26 eV are observed with increase of the substrate temperature. The refractive index values are in the range of 2.55–2.92 for the films deposited at different substrate temperatures. It is observed that the conductivity increases continuously with temperature. Laser Raman studies indicated the presence of peaks at 206.9 and 412.2 cm-1corresponding to the first order and second order LO phonon

Influence of substrate temperature on the properties of electron beam evaporated ZnSe films

ZnSe films were deposited on glass substrates keeping the substrate temperatures, at room temperature (RT), 75, 150 and 250 °C. The films have exhibited cubic structure oriented along the (111) direction. Both the crystallinity and the grain size increased with increasing deposition temperature. A very high value of absorption co-efficient (104 cm-1) is observed. The band gap values decrease from a value of 2.94 eV to 2.69 eV with increasing substrate temperature. The average refractive index value is in the range of 2.39 – 2.41 for the films deposited at different substrate temperatures. The conductivity values increases continuously with temperature. Laser Raman spectra showed peaks at 140.8 cm-1, 246.7 cm-1 and 204.5 cm-1 which are attributable to 2TA LO phonon and TO phonon respectively

Structural, optical, and electrical properties of electron beam evaporated CdSe thin films

CdSe films have been deposited on glass substrates at different substrate temperatures between room temperature and 300 °C. The films exhibited hexagonal structure with preferential orientation in the (002) direction. The crystallinity improved and the grain size increased with temperature. Band gap values are found decreasing from about 1.92 eV to 1.77 eV with increase of the substrate temperature. It is observed that the resistivity decreases continuously with temperature. Laser Raman studies show the presence of 2 LO and 3 LO peaks at 416 cm-1 and 625 cm-1 respectively