Isotype n-Si/n-Bi2O3 Heterojunctions Designed as High-Frequency MOS Devices, Microwave Band Filters and Quad Band 5G/6G Antennas

Herein, a hybrid device structure is designed for high-frequency applications. The device is fabricated by the thermal evaporation of n-Bi2O3 nanosheets onto n-Si substrates to form an isotype heterojunction encapsulated between two Schottky barriers (Ag/n-Si, Pt/n-Bi2O3). The hybrid-structured device exhibits metal-oxide-semiconductor (MOS) characteristics that can be depleted in the frequency domain of 1-70 MHz. The complex device structure exhibits two identical flat-band built-in potentials with a value of 0.97 eV. MOS devices display a charging/discharging cycle within a time scale of 14.3 ns. In addition, when experimentally tested as band-pass/reject filters in the quad-band range of 0.01-1.80 GHz, the device shows a high cutoff frequency up to similar to 19 GHz at a quad frequency of 1.80 GHz. Moreover, when employed as a multiport 5G/6G antenna using a network analyzer working in the frequency domain of 1.0-6.0 GHz, the devices show promising antenna characteristics suitable for the targeted technology applications. Specifically, the measured reflection and transmission coefficient parameters for the two-port antenna designs show isolation parameters down to -24.5 dB. The features of the two-port antennas, which demonstrate good isolation between transmitted signals, are promising for use of the Ag/n-Si/n-Bi2O3/Pt hybrid devices in high-frequency networks including 5G/6G technology.