THz plasmonics and electronics in germanene nanostrips

Germanene nanostrips(GeNSs)have garnered significant attention in modern semiconductor technology due to their exceptional physical characteristics,positioning them as promising candidates for a wide range of applications.GeNSs exhibit a two-dimensional(buckled)honeycomb-like lattice,which is similar to germanene but with controllable bandgaps.The modeling of GeNSs is essential for developing appropriate synthesis methods as it enables understanding and controlling the growth process of these systems.Indeed,one can adjust the strip width,which in turn can tune the bandgap and plasmonic response of the material to meet specific device requirements.In this study,the objective is to investigate the electronic behav-ior and THz plasmon features of GeNSs(≥100 nm wide).A semi-analytical model based on the charge-carrier velocity of free-standing germanene is utilized for this purpose.The charge-carrier velocity of freestanding germanene is determined through the GW approximation(V_(F)=0.702×10^(6)m·s^(−1)).Within the width range of 100 to 500 nm,GeNSs exhibit narrow bandgaps,typi-cally measuring only a few meV.Specifically,upon analysis,it was found that the bandgaps of the investigated GeNSs ranged between 29 and 6 meV.As well,these nanostrips exhibit√q-like plasmon dispersions,with their connected plasmonic fre-quency(≤30 THz)capable of being manipulated by varying parameters such as strip width,excitation plasmon angle,and sam-ple quality.These manipulations can lead to frequency variations,either increasing or decreasing,as well as shifts towards larger momentum values.The outcomes of our study serve as a foundational motivation for future experiments,and further con-firmation is needed to validate the reported results.

Mechanism of Fixation of Ozone and Its Medical Value

Because of both ozone gas and ozone solution are instable which limits the application of ozone, to solve the storage problem, it is necessary to find a kind ofideal ozone carrier which can combine ozone as an ＂ozonic compound＂ in which the bond strength between ozone and carrier should not be too high or too low, to appropriately release ozone from the ozonic compound. Combining Criegee’s three-step reaction mechanism of ozone and olefins, the charge, covalent bond levels and energy levels of ozone, ethylene, butadiene and their ozonic compounds were calculated by the first-principles calculation method based on density functional theory methods. The stability of the ozonide, or the bond strength between ozone and ions of carrier were controlled felicitously to release ozone from the ozonide with proper velocity. Ozone antimicrobial was composed on the above principle. It can be used conveniently, especially for common families.

Prospects of gallium nitride double drift region mixed tunneling avalanche transit time diodes for operation in F, Y and THz bands

The potential of GaN as a wide band gap semiconductor is explored for application as double drift region mixed tunneling avalanche transit time （MITATT） diodes for operation at 120 GHz, 220 GHz and 0.35 THz using some computer simulation methods developed by our group. The salient features of our results have uncovered some peculiarities of the GaN based MITATT devices. An efficiency of more than 20% right up to a frequency of 0.35 THz （from the GaN MITATT diode） seems highly encouraging but a power output of only 0.76 W is indicative of its dismal fate. The existence of a noise measure minimum at the operating frequency of 0.35 THz is again exhilarating but the value of the minimum is miserably high i.e. more than 33 dB. Thus, although GaN is a wide band gap semiconductor, the disparate carrier velocities prevent its full potential from being exploited for application as MTATT diodes.