Optimal algorithm for spray pyrolysis deposition of TiO2 films by using an industrial robot

Abstract

This paper approaches the optimization of the spray pyrolysis deposition (SPD) using an industrial robot. The purpose is to develop an optimal algorithm for obtaining uniform films on a planar surface. The design objective refers to the uniformity of the film, the aim being to optimize the difference in thickness between two specific points on the sample. The characteristic parameters of the SPD process (the substrate temperature, the height of spraying cone, the spraying angle, the carrier gas pressure, the trajectory step, the time between two passes, and the number of consecutive passes on the substrate) are used as design variables in the optimization. The investigation strategy is based on a design of experiments technique (PlackettBurman), obtaining the appropriate regression function. The goodness-of-fit has been verified by computing the variance in the predicted results versus the real data, the probability that the fitted model has no useful terms, and the significance of the regression. Experimental results are used to validate the optimization algorithm.

Development of automated spray pyrolysis setup for chemical vapour deposition like growth of thin solid films

“…Similar results have been claimed [43,44] for substrate temperatures greater than 400 • C. The decrease in substrate temperature, about 50 • C, might be due to the coupled effect of substrate temperature on the reduced initial droplet size. The plausible scientific rationale, for the deposition of the quality thin films at reduced substrate temperature, is given in the earlier report [34]. Hence, the n-SP method can be employed to deposit the thin films at lower substrate temperature.…”

“…These add-ons will again increase the initial investment and operational cost. Hence, for droplet sizes with narrow size distribution and consequently the improved uniformity of the films, the therapeutic aerosol nebulizer could be used as an economical choice to the add-ons discussed above [34]. Due to the narrow size distribution of the droplets, uniform and smooth CVD-like thin films with nominal growth rate can be prepared [32,34,35] by nebulizer spray pyrolysis.…”

“…Also, the droplet residing time inside the furnace determines the deposition mechanism [40] of thin films such as amorphous, crystalline powder, and vapor deposited thin films. If the decomposition of droplet evolution is occurring on the surface of the substrates, the vapor is deposited on the substrates, and hence the film quality will be almost comparable to the chemical vapor deposited thin films [34]. Hence, to achieve the CVD-like thin film deposition using spray pyrolysis, the type of furnace is also a crucial parameter, along with the size of the initial droplet.…”

Design of the User Interface for a Robotic Spray Pyrolysis System to Deposit Thin Films

“…Principle of SPD technique includes a nozzle tube connected to a gas that creates pressure in the precursor solution which is sprayed onto a heated surface. The heated plate is necessary to maintain constant the substrate temperature throughout the spray pyrolysis process [5,6].…”