Magnetron Sputtering In Argon Atmosphere Research Articles

Characterization of CdS sputtering deposition on low temperature pulsed electron deposition Cu(In,Ga)Se2 solar cells

The present paper reports the investigation of sputtered CdS as a buffer layer in Cu(In,Ga)Se2 (CIGS) solar cells, for a dry-low temperature all in-line production technology method. The CdS film is deposited using radio-frequency magnetron sputtering in argon atmosphere. Compared to the well-known CdS grown by chemical bath deposition, the sputtering technology is feasible for the serial manufacturing process. The morphology and optical transmittance of CdS thin films are studied, as well as the CdS/CIGS interface and the solar cell characteristic. We observe that CdS layer deposited on glass is uniform and continuous with optical transmittance above 90% in the wavelengths range corresponding to the energy gap of the absorber. Current density-voltage (J-V) curve shows an overall efficiency of 6% affected by inhomogeneity at the CIGS/CdS interface. Sputtering deposition is not able to create a homogeneous layer on the absorber irregularities due its growth process. Moreover, Auger depth profile shows oxygen contamination at the interface, due to absorber surface oxidation. Within this work, the main crucial aspects of a new solar cell production technology, as well as related solutions, are reported.

Single Crystal, High Band Gap CdS Thin Films Grown by RF Magnetron Sputtering in Argon Atmosphere for Solar Cell Applications

Single Crystal, High Band Gap CdS Thin Films Grown by RF Magnetron Sputtering in Argon Atmosphere for Solar Cell Applications

Surface and optical properties of indium tin oxide layer deposition by RF magnetron sputtering in argon atmosphere

This study focused on the characterization and properties of transparent and conductive indium tin oxide (ITO) thin films deposited in argon atmosphere. ITO thin films were coated onto glass substrates by radio frequency (RF) magnetron sputtering technique at 75 and 100 W RF powers. Structural characteristics of producing films were investigated through X-ray diffraction analysis. UV–Vis spectrophotometer and interferometer were used to determine transmittance, absorbance and reflectance values of samples. The surface morphology of the films was characterized by atomic force microscope. The calculated band gaps were 3.8 and 4.1 eV for the films at 75 and 100 W, respectively. The effect of RF power on crystallinity of prepared films was explored using mentioned analysis methods. The high RF power caused higher poly crystallinity in the produced samples. The thickness and refractive index values for all samples increased respect to an increment of RF power and were calculated as 20, 50 nm and 1.71, 1.86 for samples at 75 and 100 W, respectively. Finally, the estimated grain sizes for all prepared films decreased with increasing of 2θ degrees, and the number of crystallite per unit volume was calculated. It was found that nearly all properties including sheet resistance and resistivity depend on the RF power.

Optical properties of thin films of titanium with transient layers on them

Within the Beattie spectroellipsometric method, we measured the ellipsometric parameters of thin Ті films deposited onto glass substrates by magnetron sputtering in argon atmosphere. Measurements were carried out at five angles of incidence with light from the visible and ultraviolet ranges of the spectrum. Using the Airy recurrent formulas, we solved the inverse problem of ellipsometry for a three-layer model of films. The model includes nine unknown quantities - three thicknesses of layers and six optical constants, namely: the refractive and absorption indices of all these layers. The results obtained show that the upper layer being in contact with air consists of titanium oxide of the TiO2 type, the second layer is made of pure metallic titanium, and, finally, the third layer adjoining the glass substrate is also oxide TiO2. It is worth noting that the optical constants of the second layer are practically identical to those of massive Ті. The calculations of the film thicknesses and optical constants by using the one-layer model gave the values significantly different from the optical constants of massive titanium. In addition, the studies of both the electric conductance of the prepared Ті films and morphology of their surface with an atomic force microscope were carried out.

Influence of nitrogen, oxygen, and water on magnetic properties of dc magnetron sputtered GdTbFe films

Amorphous GdTbFe thin films were produced by dc magnetron sputtering in argon atmosphere at varying partial pressures of nitrogen, oxygen, and water. The compensation temperature Tcomp, the Curie temperature TC, and the uniaxial magnetic anisotropy constant Ku decrease strongly with increasing impurity concentration in the films. The influence of nitrogen on Tcomp and Ku is about a factor of 3 less than that of oxygen and water. The strong decrease of Tcomp and Ku is due to the preferred reaction of the impurities with the rare-earth (RE) atoms. This leads to a preferred deactivation of the latter resulting in a decrease of the rare-earth (RE) sublattice magnetization. Moreover, the uniaxial magnetic anisotropy is primarily based on the single ion anisotropy of the Tb atoms. If these are deactivated Ku decreases. At increasing impurity concentrations the selectivity of deactivation decreases and increasing amounts of Fe are affected. Thus, the steepest decrease of Tcomp and Ku is observed at low concentrations. For Tcomp the mean values of the slopes at concentrations below 1 at. % are 35 K per at. % for nitrogen, 85 K per at. % oxygen (Ar/oxygen atmosphere), or 125 K per at. % oxygen (Ar/water atmosphere). Ku is reduced to half its original value at concentrations of 4 at. % nitrogen, 1.2 at. % oxygen (Ar/O2), and 0.9 at. % oxygen (Ar/H2O) in the films. The Curie temperature TC decreases at a rate of about 10 K per at. % impurity. This is due to the diminishing magnetic interactions at increasing impurity incorporation.