Electron and hole traps in N-doped ZnO were investigated using a structure of n + -ZnO:Al/ i-ZnO/ ZnO:N grown on a p-Si substrate by metalorganic chemical vapor deposition ͑for growth of the ZnO:N layer͒ and sputtering deposition ͑for growth of the i-ZnO and n + -ZnO:Al layers͒. Current-voltage and capacitance-voltage characteristics measured at temperatures from 200 to 400 K show that the structure is an abrupt n + − p diode with very low leakage currents. By using deep level transient spectroscopy, two hole traps, H3 ͑0.35 eV͒ and H4 ͑0.48 eV͒, are found in the p-Si substrate, while one electron trap E3 ͑0.29 eV͒ and one hole trap H5 ͑0.9 eV͒ are observed in the thin ZnO:N layer. Similarities to traps reported in the literature are discussed.