The Effect of Doping with N and Cu Atoms on the Hydrogen Sensing Properties of the ZnO\( \left( {10\bar{1}\varvec{ }0} \right) \) Surface and ZnO Nanowires: A First-Principles Study

The effect of doping with acceptor atoms such as copper and nitrogen on the electronic structure and hydrogen sensing properties of the ZnO\( \left( {10\bar{1}\varvec{ }0} \right) \) surface and the ZnO nanowires was investigated using the first principles method. Our results show that the doping process can greatly affect the electronic structure of ZnO surfaces and nanowires, and consequently their responses to hydrogen adsorption can be significantly enhanced after doping with acceptors. We found that hydrogen adsorption is more favored on the doped ZnO\( \left( {10\bar{1}\varvec{ }0} \right) \) surface than onto the clean surface, and this makes the Cu-doped and the N-doped surfaces more efficient for H gas sensing applications than clean ZnO surface. Our results show also that the Cu-doped surface is more efficient for the H₂ sensing applications than the N-doped surface however the N-doped surface is better for the atomic hydrogen sensing applications. We have also examined the effect of doping with Cu and N on the hydrogen sensing properties of the ZnO nanowires. The obtained results show that the H gas sensing properties of the undoped ZnO nanowires are many times better than those of the ZnO\( \left( {10\bar{1}\varvec{ }0} \right) \) surface. We found also that, the doping process can greatly enhance the atomic hydrogen sensing properties of the ZnO nanowires.