Design and detailed electrical characterization of MoO3 supported Au/n-Si junction diodes

Abstract

In this study, the effect of molybdenum trioxide (MoO₃) nanopowder as a thin film layer on the performance of junction diodes was investigated and the fabrication of Au/MoO₃/n-Si/Al device structure with this material was achieved. In the experimental process, Al was thermally deposited on one surface of the silicon wafer and annealed at 450 °C for 10 min to establish an ohmic contact. A thin film of MoO₃ approximately 15 nm thick was deposited on the n-Si surface by thermal evaporation at a 10⁻⁷ Torr high vacuum. On top of this layer, a 100 nm Au layer was deposited by thermal evaporation using a circular mask. The reference Au/n-Si/Al diode was fabricated under identical conditions without the MoO₃ layer to evaluate the influence of the oxide interlayer on the device characteristics. The electrical performance of the devices was characterized through I–V measurements at 300 K. The diode parameters, including the barrier height (BH) and the ideality factor (IF), were extracted using the TE theory and further analyzed using the Cheung and Norde techniques. The BH (Φ_b) and IF (n) values of the reference Au/n-Si/Al diode were calculated as 0.65 eV and 2.06, respectively. In contrast, the diodes with the MoO₃ interlayer exhibited Φ_b values ranging from 0.70 to 0.73 eV and n values between 1.69 and 1.73. The increased IF was attributed to the influence of series resistance, while the variations in BH were related to the properties of the MoO₃/n-Si interface. Among the devices fabricated, the diode with the best performance (referred to as device 2) showed an IF of 1.69 and a BH of 0.73 eV. This device was selected for detailed analysis and its characteristics were further examined using the Cheung and Norde methods. In addition, C–V, G-V, and Z-V measurements at various frequencies were used to derive key device parameters, particularly the BH, highlighting the role of frequency-dependent behavior.