n-Si/p-BaO/p-SiO2 Heterojunctions Designed as Negative Capacitance and Negative Conductance Sources, 6G Technology Frequency Stabilizers, and Current Rectifiers

Barium oxide thin films were deposited on n-type Si wafers and coated with silicon oxide nanosheets to develop multifunctional electronic devices. Two channels, n-Si/p-BaO (SB) and n-Si/p-BaO/p-SiO₂ (SBS), were fabricated under high vacuum (10⁻⁵ mbar). The SB channel served as a microwave resonator and a negative capacitance (NC) source, while the SBS channel exhibited suppressed NC and a negative conductance (NG) effect. NC and NG effects dominate in the frequency ranges of 1.18-1.80 GHz and 1.16-.80 GHz, respectively. Both channels demonstrated high cutoff frequencies exceeding 200 GHz, making them effective as 6G band filters and high-frequency stabilizers. Additionally, the current-voltage characteristics revealed strong temperature dependent asymmetry, with ratios of 52 and 132 at 5.0 V for SB and SBS, respectively, enabling their use as electronic switches and current rectifiers even at 433 K. These devices combine NC and NG features, high-frequency stabilization, and current rectification, showcasing their potential for advanced multifunctional applications.