Tin Oxide n- type Semiconductor Inverted to p- type Semiconductor Prepared by Sol-gel Method

Tin oxide thin films doped with iron were deposited on glass substrate, using codeposition dip coating sol-gel technique, the films were doped with iron oxide at different concentration (%2,%5,%7,%10).The samples were called (S2,S5,S7,S10).Then it's sintered for 2 hour at temperature 600 °C. The electrical properties of the samples that were called (S2,S5,S7,S10) were studied by DC and AC measurements. From DC measurement, the potential high between the grain boundary of the sample was determined. From AC measurement, by drawing the relationship between complex part and real part of the complex impedance. we note that figures of the impedance spectrum have a semi-cycle which means that it is due to Debye model that involves the grain to be homogenous. Then the activation energy was determined by using AC and DC measurement. The density of free charge was determined as well as the density of trapped state determined too for the whole samples,too. By using Mott Schottky relationship we determined type semiconductor.