Electron and hole traps in N-doped ZnO grown on p-type Si by metalorganic chemical vapor deposition

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 layer) and sputtering deposition (for growth of the i-ZnO and n(+)-ZnO:Al layers). 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 eV) and H4 (0.48 eV), are found in the p-Si substrate, while one electron trap E3 (0.29 eV) and one hole trap H5 (0.9 eV) are observed in the thin ZnO:N layer. Similarities to traps reported in the literature are discussed.