Microstructural, chemical and electrical characteristics of Au/magnetite (Fe3O4)/n-GaN MIS junction with a magnetite interlayer

Magnetite (Fe₃O₄) layers were prepared on n-type GaN surface by the e-beam method and its microstructural and compositional characteristics were evaluated by XRD, XPS and TEM techniques. The XRD, XPS and TEM evaluations confirmed the formation of the Fe₃O₄ layer on the n-GaN surface. Then, the Au/Fe₃O₄/n-GaN metal/interlayer/semiconductor (MIS) junction was fabricated and its electrical properties investigated with the I-V and C-V approaches. The MIS junction showed a good rectification nature with a high barrier height (0.83 eV) compared to the SE (0.71 eV). This implies that the barrier height was markedly affected by the Fe₃O₄ layer. Further, the barrier height was extracted by means of Cheung's, Norde and ψ_S-V plot and it was found that the values are nearly matched with one another, indicating that the methods used were consistent and valid. The frequency-dependent properties of the MIS and SE junctions have also been discussed. The interface state density (N_SS) of the MIS junction was found to be lower than the SE, indicating that the Fe₃O₄ layer plays a vital role in the decreased N_SS. Based on the analysis, it can be concluded that the Fe₃O₄ layer is an apt material for the fabrication of new electronic device applications.