Nanohybrids that consisit of p-type, nitrogen-doped ZnO and graphene nanostructures: synthesis, photophysical properties, and biosensing application

ZnO, a promising material for optoelectronic applications, has attracted considerable attention due to its wide and direct band gap and large exciton binding energy. To understand the applications of this material, fabrication of high quality p-type ZnO is a key step. However, a reliable p-type doping of this material remains a major challenge. In this study, we report p-type nitrogen-doped ZnO nanoparticle, grown in a nitrogen doped graphene layer matrix by a plasma heating process using a natural protein and zinc nitrate as the precursors. The structural characterizations are developed by several microscopic techniques including the field emission electron microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and micro-Raman analysis. In addition, the ultraviolet (UV)-visible absorption characteristics and photoluminescence properties of the samples are studied. Its p-type conduction behaviour is confirmed by the Hall effect measurement, which was ascribed to the high nitrogen dopant concentration in the Zn-poor ZnO, and the related mechanism for the p-type behaviour is also discussed. Moreover, the results of the glucose detection based on the strong green luminescence of glucose indicate that the nitrogen-doped ZnO nanodots/nitrogen-doped graphene layer nanohybrid is also a competitive candidate in the biosensing field.