Current-voltage characteristics of zinc oxide nanorods hydrothermally grown on a p-type silicon substrate
We present the current-voltage (I-V) characteristics of zinc oxide (ZnO) nanorods grown hydrothermally on a p-type silicon (Si) substrate. The vertically aligned hexagonal ZnO nanorods are synthesized directly on the substrate surface and have diameters and lengths of 390 to 570 nm and 1.15 µm, respectively. With good rectifying I-V behavior, the nanorods form a p-n junction with the Si substrate. When exposed to UV illumination, the p-Si/n-ZnO heterojunction also exhibits currents higher than without UV illumination resulting in an average contrast (photo-to-dark current) ratio of 1.21. Although the device fabrication still needs to be optimized to minimize the series resistance and ideality factor, our results suggest that similar heterojunction designs can be used for modern photodetector devices.