The Effect of Post-Annealing Temperatures on Rectifying Properties of Anisotype Al/ZnO/p-Si/Al Heterojunctions

Here we report on the impact of low annealing temperatures on the electrical properties of pn junction based on zinc oxide (ZnO as an n-type semiconductor) and p-type silicon (p-Si). Initially, ZnO was deposited over p-Si substrates through a sputtering process. Subsequently, the samples were post annealed at low temperatures in the range of 100 degrees C to 300 degrees C. Then, the samples were metalized for the contacts. The devices were characterised for their crystal structures and morphologies through X-ray diffractometer and field-effect scanning electron microscopy. Further, the current-voltage characteristics were measured as a function of annealing temperatures. The results of fabricated pn junction reveal a high rectification ratio of the prepared junctions. In addition, it was found that the annealing temperatures play a significant role in the junction parameters (namely, the barrier height and the ideality factor). The barrier height values of the prepared junction were reduced from 0.877 to 0.752 eV. The ideality factor values followed the same trend and decreased from 6.65 to 3.54. The findings of this study demonstrated that increasing the annealing temperature enhanced the electrical properties of the ZnO-based diode.