Study of functional properties stability of SnO2 films on the duration thermal exposure and temperature changes

Thin films of tin oxide and composite systems based on them have found the greatest applications in solar energy. The properties of oxides depend on the obtaining technology and following processes. The choice of the optimal solution maturation time influences the functional properties of the films. In this research, solutions with the adding different volume of concentrated aqueous solution of ammonia (NH4OH) per 100 ml of the system were prepared: 0.8 ml (pH=1.40), (pH=1.46) and 1.6 ml (pH=1.49). This enabled the study of the properties of films obtained from solutions of different acidity. The resistance of the films was measured in the 10 different parts of the films. In addition, the effect of the isothermal annealing time at 2500C on the structural and optical properties of the samples was investigated. As a result of this study, there was found the correlation between an increase in the duration of annealing and a decrease in the transparency of films obtained from the SnCl4/EtOH. The annealing at temperature 2500C within 6 hours led to a change in transparency of films from 93% (λ=550nm) to 88%. The further increase of the annealing duration up to 9 hours does not affect the transparency of film

THE EFFECT OF DEPOSITION TECHNIQUE ON FORMATION OF TRANSPARENT CONDUCTIVE COATINGS OF SnO2

The producing technology of transparent conductive layers is the basis for many optoelectronic devices. To increase transparency and conductivity at low-cost and controlled methods is an important challenge. Studied samples of SnO2 coatings were obtained by sol-gel method. The deposition of films on glass substrates was carried out by dip coating, spin-coating and sprays-pyrolysis methods. According to micro-weighing, the film thickness varies from 250 nm to 290 nm. The layer with the most uniform thickness was achieved using spray pyrolysis. Films deposited by this technique exhibit the greatest transparency and lowest resistance. It is important to note that these samples have the minimum scatter of resistance values depending on the surface area. In case dip coating technique the resultant film contains open- and closed-type blisters. This confirms the fact of inhomogeneous surface morphology of these films. X-ray diffraction analysis showed that films obtained by spin-coating and dipping methods contain SnO2 crystallites, the size of which does not exceed 10.3 nm; while films obtained by spay pyrolysis are amorphous. This is because the formation of the structure in the spay pyrolysis proceeds faster due to the substrate heating