Au/CdBr₂/SiO₂/Au Straddling‐Type Heterojunctions Designed as Microwave Multiband Pass Filters, Negative Capacitance Transistors, and Current Rectifiers

Abstract

Herein, SiO2 nanosheets with thicknesses of 25−100 nm are used to enhance the performance of Au/CdBr2 Schottky barriers. The Au/CdBr2/SiO2/Au straddling‐type heterojunction devices are prepared by the thermal evaporation technique. It is observed that SiO2 layers enhance the crystallinity of CdBr2 through increasing the crystallite sizes and decreasing the defect density, stacking faults, and microstrain by 50%, 56%, 32%, and 34%, respectively. A work function of 6.38 eV is determined from the temperature‐dependent electrical resistivity measurements of p − type CdBr2. In addition, it is observed that, when coated with 50 nm‐thick SiO2, the Au/CdBr2/SiO2/Au straddling‐type transistors can reveal high current rectification ratios of 6.9 × 102 at low biasing voltages in the range of 0.06−0.30 V. The alternating current signals’ analysis in the microwave range of spectra indicates that the current conduction mechanism is dominated by the correlated barrier hopping and quantum mechanical tunneling. It is observed that the Au/CdBr2/SiO2/Au devices exhibit a negative effect accompanied with resonance−antiresonance in the capacitance spectra. Moreover, the microwave cutoff frequency which reaches ≈165.1 GHz and the magnitude of reflection coefficient spectra show that the device under study can perform as multiband pass/stop filters suitable for wire/wireless communication applications including 3G/4G technologies.

Growth and Characterization of Lanthanum Germanide Thin Films by the Thermal Evaporation Technique

“…The high transparency of the films indicates that La 6 Ge thin films can serve as optical windows. [ 24 ] In addition the reflectance spectra which are shown in Figure 2b displays three valleys centered at 328 nm (3.78 eV), 483 nm (2.57 eV), and 875 nm (1.42 eV) and two peaks centered at 393 nm (3.16 eV) and 609 nm (2.04 eV). They provide information about resonant dielectric responses of the La 6 Ge films.…”

Yb/Se/WO3/Yb Thin Film Transistors as Rectifiers, N‐Channel Metal Oxide Semiconductor Capacitors, Laser Sensors, and Microwave Bandstop Filters

“…However, when comparing the rectification ratio of the tabulated device structures with our devices one may observe that the currently proposed devices need further issues to fit well with some of the reported rectification ratios in Table 2. Possible reasons for the low rectification ratios include the current conduction by tunneling, [ 40 ] relatively large leakage current or recombination losses due to surface trap states that existed in Se/WO 3 films, [ 41 ] and ion migration mediated by vacancies. [ 42 ] Another feature that is worth of considering is the turn‐on voltage () of the devices.…”