Determination of electrical and photoelectrical properties of Y:CdO/p-Si heterojunction

In this study, p-Si semiconductor with (100) orientation and resistivity of 1-10 Ωcm was used. Yttrium-doped and undoped cadmium oxide thin films were prepared on p-Si by using spin coating method. Aluminium was thermally evaporated in high vacuum environment. Therefore, Al/Y:CdO/p-Si structures were formed. Current-voltage (I-V) measurements of Al/Y:CdO/p-Si structures were performed in the dark at room temperature. It is noted that the the structures showed rectification feature from I-V graphics. Ideality factors and parameters such as diode barrier height were determined using lnI-V plot. Ideality factor for Al/CdO/p-Si structure was calculated as 2.45 and the ideality factor for Al/Y:CdO/p-Si structures have fallen to 1.84 value in other words diodes got closer to the ideal behavior. Y-doped CdO interlayer to increased barrier height. F(V) -V graphs were plotted using the modified Norde functions. From this plot, the series resistance and barrier height was calculated. In addition, I-V measurements of the Al/Y:CdO/p-Si were repeated under light which had intensity of 100 mW/cm2. It was observed that reverse bias current of the diode increased with the light intensity. Therefore, the structure showed fotodiode characteristic and it can be used in optoelectronic applications.