Influence of Annealing Temperature on Structural and dc Electrical Properties of SnO2 Thin Films for Schottky Barrier Diodes

This paper reports about the influence of annealing temperature on the structural, morphological, optical and electrical properties of SnO2 thin films prepared by the spin-coating method. The structural analysis reveals the presence of rutile SnO2 with tetragonal structure and its defects are reduced in higher annealing temperatures. SEM images show that the size of the grains was improved due to increase in annealing temperature. From UV-visible analysis, band gap energy (E-g), refractive index (n), and extinction coefficient (k) are estimated. The band gap energy increases from 3.46 to 3.54 eV with annealing temperatures. dc analysis shows that the Arrhenius conduction mechanism has a profound influence on the electrical conductivity and varies in the range 1.08-6.80 x 10(- 8)(Omega cm)(- 1) with annealing temperature. The Al/n-SnO2/p-Si Schottky barrier diode parameters such as ideality factor (n), barrier height (4 Phi(B)), leakage current (I-0) and series resistance (R-s) were studied by the I-V method as a function of annealing temperature as per the Thermionic Emission method (TE). The barrier height varies from 0.84 to 0.73 eV and the device ideality has improved at higher annealing temperature.