Characterization and applications of ITO/SeO2 interfaces

2023

Phys. Scr.

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Herein n-Si/p-SiO2 interfaces comprising layers of p-SeO2 are employed as an optically controllable microwave resonators. The stacked layers of SeO2 (500 nm) and SiO2 (50 nm) were deposited onto n-type Si thin crystals by the thermal evaporation technique under a vacuum pressure of 10-5 mbar. Ytterbium and Au metals were coated onto SiO2 and Si layers, respectively, to form Schottky arms. Energy band diagram analyses were performed to confirm the formation of doubled conduction and valence band offsets. These offsets create energy barriers and potential wells that contribute to the bistable behavior. Photo-impedance spectroscopic measurements were conducted on the device under blue light, demonstrating its ability to function as a light-power tunable microwave resonator and MOS capacitor. In the absence of light, negative capacitance (NC) effects were observed above a driving frequency of 1.07 GHz. As the device was exposed to light and the light power increased, the frequency range of NC effects shifted to higher driving frequencies. Furthermore, the range of NC effects became narrower with increasing light power, indicating a more limited frequency range for the manifestation of negative capacitance. In addition, n-Si/p-SeO2/p-SiO2 microwaves resonators displayed high cutoff frequency exceeding 0.10 THz at driving frequency of 1.07 GHz in the dark. The driving frequency also shifted toward larger values as light power is increased indicating the ability to optically control the cutoff frequency range and value. The high response of the capacitance, conductance, cutoff frequency spectra and the dependence of capacitance-voltage characteristics on incident light power nominate the device as microwave resonators and MOS electro-optic devices suitable for 5G/6G communication technology.

Section: Resultsmentioning

confidence: 99%

Optically controlled n −Si/p −SeO₂/p −SiO₂ microwave resonators designed for 5G/6G communication technology

2023

Phys. Scr.

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“…Electric field ionization of shallow impurity levels involves quantum‐mechanical tunneling process in which the trapped charge tunnels out from the impurity levels under the influence of the applied field. [ 36,37 ]…”

Section: Resultsmentioning

confidence: 99%

“…Electric field ionization of shallow impurity levels involves quantum-mechanical tunneling process in which the trapped charge tunnels out from the impurity levels under the influence of the applied field. [36,37] From practical point of view, Pt/MgSe/Pt structures can form tunneling-type devices. Tunneling-type devices are employable as microwave resonators, band filters, and negative conductance and negative capacitance sources.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Optical and Electrical Interactions at the Pt/MgSe Interfaces Designed for 6G Communication Technology

Algarni

Khusayfan

2022

Cryst. Res. Technol.

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Magnesium selenide thin films are coated onto glass and semitransparent Pt substrates (nanosheets) by the vacuum evaporation technique under a vacuum pressure of 10 −5 mbar. The effect of Pt nanosheets of thicknesses of 100 nm on the structural, compositional, optical, and electrical properties of MgSe is explored. It is found that platinum nanosheets enhance the light absorbability in the visible and infrared ranges of light. They slightly redshift the energy bandgap and decrease the dielectric constant. The strong interaction between Pt and MgSe increases the electrical conductivity by five orders of magnitude. Pt forms shallow impurity levels in the energy bandgap of MgSe allowing the tunneling process at the Pt/MgSe interfaces. Practically, a Pt/MgSe/Pt tunneling type device is fabricated and tested by the microwave impedance spectroscopy technique. It is found that Pt/MgSe/Pt devices can exhibit resonance-antiresonance and negative capacitance effects which are important in electronic circuits as parasitic capacitance cancelers, signal amplifiers, and noise reducers. In addition, evaluation of the cutoff frequency spectra has shown the ability of using the Pt/MgSe/Pt devices as microwave resonators appropriate for 5G/6G technologies. A cutoff frequency larger than 70 GHz can be achieved by imposing ac signal of amplitude of 0.10 V.

“…MgSe thin films coated onto Si wafers displayed photodiode characteristics with large current rectification ratios up to 10 4 and high current responsivity of 0.70 A W −1 when exposed to infrared light [8]. Based on our previous knowledge which showed that ITO substrates have enhanced the dielectric response in As 2 Se 3 [9] and in SeO 2 [10] microwave band filters, we will attempt to follow the same process for MgSe. Particularly, we have deposited MgSe films onto ITO substrates and studied their structural morphological, optical and electrical properties.…”

Section: Introductionmentioning

confidence: 99%

ITO/MgSe interfaces designed as gigahertz/terahertz filters

Almotiri

2023

Phys. Scr.

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Herein a new class of MgSe gigahertz/terahertz band filters operatives in the frequency domain of 1.0 GHz-1.86 THz is fabricated and experimentally tested. MgSe band filters are coated onto glass and indium tin oxide (ITO) substrates by the thermal evaporation technique under a vacuum pressure of 10-5 mbar. Thin films of MgSe are structurally, morphologically, compositionally, optically and electrically characterized. It is observed that ITO substrates induce the growth of monophasic of MgSe, enhances the crystallinity of the films and blueshifts the energy band gaps of MgSe. Practical applications were verified by impedance spectroscopy technique through imposing an ac signal of driving frequency in the domain of 10.0 MHz-1.8 GHz between the terminals of ITO/MgSe/Au (IMA) devices. It is observed that the IMA devices exhibit negative capacitance effect. Analysis of the cutoff frequency spectra has shown that IMA devices can reveal wide range of tunability in the gigahertz frequency domain. In addition, the cutoff frequency spectra show values reaching ~1.86 THz for signals of driving frequencies of ~1.0 GHz. Evaluation of the magnitude of the reflection coefficient spectra and return loss spectra for these devices show that the IMA devices can perform as bandstop filters with return loss values exceeding 20 dB at 1.0 GHz. The features of the ITO/MgSe/Au devices are appropriate for the 5G/6G technology needs indicating that the device can be employed in communication technology and other gigahertz/terahertz applications.