Two-dimensional
MA2Z4, as another system
of a two-dimensional material family, can obtain different materials
and considerable properties by replacing the elements M, A, and Z.
At present, the physical properties and optical response of MA2Z4 materials have been studied, but there is still
a lack of research on the application of MA2Z4 as a transistor channel material to investigate its transistor performance.
Here, we employ WGe2N4 as a representative to
systematically study the bounce-to-transport properties and gate control
capability of ML WGe2N4 field effect transistors
below 10 nm via ab initio quantum transport calculations. Until the
channel length is down to 3.0 nm, the optimized n/p-type doped WGe2N4 metal–oxide–semiconductor field-effect
transistors with proper concentrations and underlap structures can
satisfy the high-performance requirements of International Technology
Roadmap for Semiconductors of 2013 version, by considering the on-current,
subthreshold swing, intrinsic delay time, and dynamic power indicator.
Therefore, we can estimate that the monolayer WGe2N4 is a competitive alternative for transistor channel materials
in the post-silicon era.
Abstract-This paper presents a new architecture for the frequency-selective digital predistortion (DPD) for two-and three-band power amplifier (PA) linearization. Also, largely spaced-signal DPD using a digital intermediate frequency (IF) technique is demonstrated. The algorithm used accounts for differential memory effects up to fifth order for bands that can be arbitrarily spaced. The simulation and experimental studies are performed using various signal sets; two-and three-band multitone signals with various tone spacing, band separation, and complementary cumulative distribution function. An improvement of 10 dB over third-order linearization is demonstrated in simulation for more than 20 dB of adjacent channel power ratio reduction. The test signal and the linearization algorithm were implemented on a field-programmable gate array. The linearization algorithm was applied to an RF amplifier at 700-900 MHz. For the two-band case, more than 15 dB on the in-band, 13 dB on the third, and 5 dB on the fifth intermodulation distortion (IMD) cancellation were achieved. For the three-band case, more than 12 dB of IMD cancellation was observed. For largely spaced signal DPD, more than 15 dB of IMD cancellation was achieved. In the three-band case, the linearization of intermodulation byproducts overlapping with the in-band distortion is found to be of critical importance.Index Terms-Digital predistortion (DPD), memory effect, multiband linearization, power amplifier (PA).
The energy bandgap is an intrinsic character of semiconductors which largely determines their properties. The ability to continuously and reversibly tune the bandgap of a single device during real time operation is of great importance not only to device physics but also to technological applications. Here we demonstrate a widely tunable bandgap of few-layer black phosphorus (BP) by the application of vertical electric field in dual-gated BP field-effect transistors (FETs). A total bandgap reduction of 124 meV is observed when the electrical displacement field is increased from 0.10V/nm to 0.83V/nm. Our results suggest appealing potential for few-layer BP as a tunable
In 1996, he joined a nonprofit governmental organization, Small Business Corporation, Shiheung, Korea. He was a Product Development Assistant Consultant until 2007, and had been involved in over 100
Efficient modulation of carrier concentration is fundamentally important for tailoring the electronic and photoelectronic properties of semiconducting materials. Photoinduced doping is potentially a promising way to realize such a goal for atomically thin nanomaterials in a rapid and defect-free manner. However, the wide applications of photoinduced doping in nanomaterials are severely constrained by the low doping concentration and poor stability that can be reached. Here, we propose a novel photoinduced doping mechanism based on the external photoelectric effect of metal coating on nanomaterials to significantly enhance the achievable doping concentration and stability. This approach is preliminarily demonstrated by an MX (M is Mo or Re; X is S or Se) nanoflake modified through a simple process of sequentially depositing and annealing an Au layer on the surface of the flake. Under ultraviolet (UV) light illumination, the modified MX achieves degenerated n-type doping density of 10 cm rapidly according to the experimentally observed >10 times increment in the channel current. The doping level persists after the removal of UV illumination with a nonobservable decrease over 1 day in vacuum (less than 23% over 7 days under an ambient environment). This photoinduced doping approach may contribute a major leap to the development of photocontrollable nanoelectronics.
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