An absorption-wavelength (alpha-lambda) and basis absorption spectrum [(ahu)(2) -hu] of Al/SnO2/p-Si (MIS) Schottky Diodes prepared by means of spray Pyrolysis technique have been investigated at constant temperature, 300 K. From the obtained results barrier height and ideality factor have calculated. Optical properties which are absorptions, transmittance and band-gap of these diodes were also investigated. To understand the surface morphologies of them, X-Ray spectroscopy and diffraction techniques have been used. The experimental results showed that in this type of diodes the crystal size was found to be a few angstroms in size. Also the preferred directions of these crystals are in the  crystallographic directions. These findings indicated that the Schottky diodes can be used in the photovoltaic solar cell applications.