Barrier inhomogeneities in Au/CdSe thin film Schottky diodes

Schottky diodes have been fabricated by depositing Au on n-type CdSe thin films using the thermal evaporation technique, and their properties have been investigated by current-voltage and capacitance-voltage measurements. At room temperature, the characteristics obey the pure thermionic emission theory and the barrier height has been found to be 0.63 eV. The barrier heights decrease, while ideality factors increase with decrease in temperature. Further, the activation energy plot does not provide the expected Richardson constant and barrier height values. The abnormal behavior of the barrier heights and the ideality factors with respect to temperature as well as the difference between the barrier heights measured from I-V and those from C-V or flat band have been explored on the basis of barrier height inhomogeneities.