Design and characterization of MoO₃/In₂Se₃heterojunctions as terahertz/gigahertz band filters suitable for visible light communications and 3G/4G technologies

Abstract

Herein, MoO 3 /In 2 Se 3 (MI) heterojunctions are fabricated by a vacuum deposition technique for use as wideband filters. The MI devices are composed of optical and electrical parts to detect visible light spectra and microwave ac signals (0.01-3.0 GHz). Basic physical characterizations on the MI devices have shown that the devices are amorphous in nature, composed of MoO 2.86 /In 2 Se 2.76 and exhibit valence and conduction band offsets of 1.62 eV and 3.10 eV, respectively. The optical conductivity analyses have shown that, the mobility and the plasmon frequency of charge carriers in the MI devices can reach 121.70 cm 2 Vs −1 and 5.39 GHz, respectively. The terahertz cutoff frequency in these heterojunctions is in the range of 0.54-4.80 THz. On the other hand, application aimed characterizations has shown that the MI heterojunctions exhibit high photosensitivity against daylight light-emitting-diode irradiation. The capacitance-voltage characteristics tests have shown that MI devices can behave as metal-oxide-semiconductor field effect transistors (MOSFET). In addition, imposing ac signals of power of −1.0 dBm and measuring the power transmitted within a band width of 5.0 MHz in the frequency domain of 0.01-3.0 GHz indicated that the MI heterojunction devices can behave as multiband bandstop filters with notch frequency value that suits 3G/4G mobile technologies. The features of the currently proposed MI devices nominate them for use as optical receivers suitable for visible light communication technology, MOSFETs and as microwave band stop filters.

Amorphous WO3 thin films designed as gigahertz/terahertz dielectric lenses

“…To gain information about the WO3 films as dielectric lenses or optical resonators we have calculated the effective (𝜀 𝑒𝑓𝑓 ), real (𝜀 𝑟 ) and imaginary (𝜀 𝑖𝑚 ) dielectric constants (𝜀 𝑒𝑓𝑓 = 𝜀 𝑟 + 𝑖𝜀 𝑖𝑚 ), optical conductivity (𝜎(𝑤); 𝑤 = 2𝜋𝑓) and gigahertz/terahertz cutoff frequency (𝑓 𝑐𝑜 =𝜎(𝑤)/𝜀 𝑟 (𝑤)). The effective, real and imaginary parts of the dielectric constant are determined from the measured reflectance and transmittance using the relations [12,21],…”

“…As illustrated in the figure, the higher the incident photon energy is, the larger the optical conductivity value. Reproducing the optical conductivity data using Drude-Lorentz approaches for optical conduction using the equation [21,12],…”

Pt/SeO2 optical receivers designed for terahertz and 5G/6G technologies

“…This large number suggests the suitability of the Pt/SeO 2 films for fabrication of tunneling devices like light emitting diodes and Esaki diodes [30,31]. co r [32]) spectra for the glass/SeO 2 and Pt/SeO 2 films. The spectra indicate large difference between the values of f co of glass/SeO 2 and Pt/SeO 2 .…”