Recently photovoltaics attracts much attention of research and industry. The multidirectional studies are carried out in order to improve solar cells performance, the innovative materials are still searched and existing materials and technology are optimized. In the multilayer structure of CIGS solar cells molybdenum (Mo) layer is used as a back contact. Mo layers meet all requirements for back side electrode: low resistivity, good adhesion to the substrate, high optical reflection in the visible range, columnar structure for Na ions diffusion, formation of an ohmic contact with the ptype CIGS absorber layer, and high stability during the corrosive selenization process. The high adhesion to the substrate and low resistivity in single Mo layer is difficult to be achieved because both properties depend on the deposition parameters, particularly on working gas pressure. Therefore Mo bilayers are applied as a back contact for CIGS solar cells. In this work the Mo layers were deposited by medium frequency sputtering at different process parameters. The effect of substrate temperature within the range of 50°C-200°C and working gas pressure from 0.7 mTorr to 7 mTorr on crystalline structure of Mo layers was studied.
Deposition technology of the three layers antireflective coatings consists of hafnium compound are presented in this
paper. Oxide films were deposited by means of e-gun evaporation in vacuum of 5x10-5 mbar in presence of oxygen
and fluoride films by thermal evaporation.
Substrate temperature was 250°C. Coatings were deposited onto optical lenses made from quartz glass (Corning
HPFS). Thickness and deposition rate were controlled by thickness measuring system Inficon XTC/2. Simulations
leading to optimization of thickness and experimental results of optical measurements carried during and after
deposition process were presented. Physical thickness measurements were made during deposition process and were
equal to 43 nm/74 nm/51 nm for Al2O3 / HfO2 / MgF2 respectively. Optimization was carried out for ultraviolet region
from 230nm to the beginning of visible region 400 nm. In this region the average reflectance of the antireflective
coating was less than 0.5% in the whole range of application.
Electrochromic system is the one of the most popular devices using color memory effect under the influence of an
applied voltage. The electrochromic system was produced based on the thin WO3 electrochromic films. Films were
prepared by RF magnetron sputtering from tungsten targets in a reactive Ar+O2 gas atmosphere of various Ar/O2 ratios.
The technological gas mixture pressure was 3 Pa and process temperature 30°C. Structural and optical properties of WO3
films were investigated for as-deposited and heat treated samples at temperature range from 350°C to 450°C in air. The
material revealed the dependence of properties on preparation conditions and on post-deposition heat treatment. Main
parameters of thin WO3 films: thickness d, refractive index n, extinction coefficient k and energy gap Eg were
determined and optimized for application in electrochromic system. The main components of the system were glass plate
with transparent conducting oxides, electrolyte, and glass plate with transparent conducting oxides and WO3 layer. The
optical properties of the system were investigated when a voltage was applied across it. The electrochromic cell revealed
the controllable transmittance depended on the operation voltage.
Experiments were carried out on single films of Co and Cu, and on Co-Cu bilayers evaporated on the NaCl(001) substrates at room temperature. A thickness of single films, measured by interferometry method, has been changed from 3 to 40 nm for Cu and from 5 to 40 nm for Co. The Transmission Electron Microscope studies showed that at annealing temperatures below 600 K the films consist of fcc Cu and hcp Co. After annealing at higher temperatures, besides the presence of phases already observed at lower temperatures, also Co-Cu solid solution together with single phase of hcp Co was observed.
Large area coatings such as infrared-mirrors and transparent heaters are widely used in buildings and vehicles. The spectral transmission and reflection of such thin films are time independent. Electrochromic (EC) systems are a new class of optical filters with voltage controlled transmission. One can choose the desired optical characteristics using a small voltage. This time dependence is very useful for different applications.