Comprehensive electrical characterization of Cr/V2O5/p-Si junction diode with V2O5 thin film at room temperature

Abstract

This study explores the device properties of vanadium pentoxide (V₂O₅) thin films in the Cr/V₂O₅/p-Si/Al junction diode structure. The experimental setup utilized p-type silicon (p-Si) wafers with a resistivity of 1–10 Ω/cm and a thickness of 400 µm, chemically cleaned using the RCA1 and RCA2 protocols. Aluminum (Al) was deposited on one surface of the wafer as a back contact and annealed at 580 °C to establish ohmic behavior. A 10 nm layer of V₂O₅ was thermally deposited on the opposite surface and followed by a 100 nm top contact of Cr was deposited by DC sputtering. For comparison, a Cr/p-Si/Al reference device was fabricated under identical conditions, excluding the V₂O₅ layer. Electrical measurements, including I–V and diode parameter analyses, were performed at room temperature using TE theory, Cheung, and Norde functions. Ideality factor (IF) and barrier height (BH) for the reference diode from the TE method were determined to be 2.03 and 0.58 eV, while the 8 V₂O₅-based devices exhibited IF values ranging from 1.89 to 1.96 and BH values between 0.68 and 0.74 eV. The best performing device, designated device 5, achieved an IF value of 1.90 and a BH value of 0.74 eV. In addition, the photodiode properties of this device were analyzed under a solar simulator. These results indicate that the incorporation of the V₂O₅ interface layer improves the barrier properties of the diode and has potential for advanced rectification and photovoltaic applications. The presence of the series resistance (SR) and interface layer in the device and the inhomogeneity of the BH are also considered as factors contributing to that increase in IF. C–V characterization, another critical technique for understanding the electrical parameters of Schottky-type devices, was used to calculate important parameters such as BH and carrier concentration for the best performing device. Furthermore, G/ω–V and Z–V measurements at different frequencies were analyzed to better understand the electrical properties and surface/interface states of the device with the V₂O₅ interface.