p-type K-doped ZnO nanorods for optoelectronic applications

Single crystalline p-type K-doped ZnO nanorods (NR) have been synthesized by convenient and low-cost solution technique. X-ray diffraction analysis confirmed the hexagonal system of K-doped ZnO nanorods and a preferred a axis orientation. The diameter and length were found to be 30–50 nm and 150–200 nm, respectively, in electron microscopic studies. The p-type nature and high hole density of 2.36×1019 per cm3 was demonstrated by Hall studies. A sharp lower cutoff and reduction in the bandgap was observed in UV-Vis study which is linked to its smaller size and p-type conduction in NR. In Photoluminescence studies, a near band emission in the UV range and a yellow emission with a blueshift were detected in the visible region in K-doped ZnO NR. The variation in intensity of peaks is correlated with the dimensions of NR. The redshift observed in Raman peaks is explained in terms of the stress developed in ZnO nanostructure due to lattice mismatch by K doping. These results provide better insight of K-doped ZnO nanostructures for both fundamental research and technological applications in optoelectronic devices.