Abstract The source/drain in an n-channel metal-oxide-semiconductor field-effect transistor (nMOSFET) with solid phase epitaxial (SPE) implanted Si: C before the spacer formation is proposed. Compared to the conventional nMOSFET with SPE implanted Si: C after the spacer formation, it brings in proximity to the device channel and shows great improvement of electron mobility via the stronger tensile strain effect.

The mechanism of forming-free bipolar resistive switching in a Zr/CeO x /Pt device was investigated. High-resolution transmission electron microscopy and energy-dispersive spectroscopy analysis indicated the formation of a ZrO y layer at the Zr/CeO x interface. X-ray diffraction studies of CeO x films revealed that they consist of nano-polycrystals embedded in a disordered lattice. The observed resistive switching was suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies in the CeO x film and in the nonstoichiometric ZrO y interfacial layer. X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions. In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism. The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).

Bipolar resistive switching memory (RRAM) relies on ion migration effects taking place at a conductive filament (CF). Understanding the evolution of the CF during set and reset transitions is essential for predicting RRAM scalability and for developing new methods for storage and computation. This work describes the evolution of the CF during bipolar resistive switching through numerical simulations of ion drift/diffusion. The defect distribution profile for increasing current after set transition and for increasing voltage during set transition are shown. Finally, the asymmetric shape of the CF is evidenced through polarity-dependent experiments and explained through numerical simulations.

The recent development of plasmonics has overcome the optical diffraction limit and fostered the development of several important components including nanolasers, low-operation-power modulators, and high-speed detectors. In particular, the advent of surface-plasmon-polariton (SPP) nanolasers has enabled the development of coherent emitters approaching the nanoscale. SPP nanolasers widely adopted metal-insulator-semiconductor structures because the presence of an insulator can prevent large metal loss. However, the insulator is not necessary if permittivity combination of laser structures is properly designed. Here, we experimentally demonstrate a SPP nanolaser with a ZnO nanowire on the as-grown single-crystalline aluminum. The average lasing threshold of this simple structure is 20 MW/cm(2), which is four-times lower than that of structures with additional insulator layers. Furthermore, single-mode laser operation can be sustained at temperatures up to 353 K. Our study represents a...

We systematically investigate the effects of surface roughness on the characteristics of ultraviolet zinc oxide plasmonic nanolasers fabricated on aluminium films with two different degrees of surface roughness. We demonstrate that the effective dielectric functions of aluminium interfaces with distinct roughness can be analysed from reflectivity measurements. By considering the scattering losses, including Rayleigh scattering, electron scattering, and grain boundary scattering, we adopt the modified Drude-Lorentz model to describe the scattering effect caused by surface roughness and obtain the effective dielectric functions of different Al samples. The sample with higher surface roughness induces more electron scattering and light scattering for SPP modes, leading to a higher threshold gain for the plasmonic nanolaser. By considering the pumping efficiency, our theoretical analysis shows that diminishing the detrimental optical losses caused by the roughness of the metallic interface could effectively lower (~33.1%) the pumping threshold of the plasmonic nanolasers, which is consistent with the experimental results.

The authors demonstrate a simple method to fabricate ultrasmooth single-crystalline silver (Ag) films with high reflectivity and low plasmonic damping. The single-crystalline Ag thin film on the clean Si (100) substrate is first deposited by electron-gun evaporator and then treated by rapid thermal annealing (RTA) to improve its quality. The crystal structure and surface morphology are characterized by x-ray diffraction, transmission electron microscopy, and atomic force microscopy. Optical constants of the prepared films are extracted by fitting the measured reflectivity spectra with the Drude model. These results show that the Ag film with 340 C RTA has the best film quality, including small surface roughness of 0.46 nm, a sharp x-ray diffraction peak with FWHM of 0.3 , and lowest damping in the visible and near-infrared wavelength regime. Therefore, our method is not only cost-effective but also useful for fabricating metal-based plasmonic and nanophotonic devices. V

Aluminum, as a metallic material for plasmonics, is of great interest because it extends the applications of surface plasmon resonance into the ultraviolet (UV) region and is superior to noble metals in natural abundance, cost, and compatibility with modern semiconductor fabrication processes. Ultrasmooth single-crystalline metallic films are beneficial for the fabrication of high-definition plasmonic nanostructures, especially complex integrated nanocircuits. The absence of surface corrugation and crystal boundaries also guarantees superior optical properties and applications in nanolasers. Here, we present UV to near-infrared plasmonic resonance of single-crystalline aluminum nanoslits and nanoholes. The high-definition nanostructures are fabricated with focused ion-beam milling into an ultrasmooth single-crystalline aluminum film grown on a semiconducting GaAs substrate with a molecular beam epitaxy method. The single-crystalline aluminum film shows improved reflectivity and redu...

Nanolasers with ultra-compact footprint can provide high intensity coherent light, which can be potentially applied to high capacity signal processing, biosensing, and subwavelength imaging. Among various nanolasers, those with cavities surrounded by metals have been shown to have superior light emission properties because of the surface plasmon effect that provides enhanced field confinement capability and enables exotic light-matter interaction. In this study, we demonstrated a robust ultraviolet ZnO nanolaser which can operate at room temperature by using silver to dramatically shrink the mode volume. The nanolaser shows several distinct features including an extremely small mode volume, a large Purcell factor, and a slow group velocity, which ensures strong interaction with the exciton in the nanowire.

It is difficult to operate plasmonic nanolasers on silver films in the ultraviolet regime owing to the bending-back effect of surface plasmon dispersion. In this paper, we report on plasmonic lasers comprised of a ZnO nanowire lying on a single-crystalline silver film with a SiO 2 spacer layer. The silver can strongly shrink the mode volume, thereby boosting the Purcell factor. Meanwhile, the SiO 2 spacer thickness is optimized to adjust the surface plasmon dispersion curve so that the lasing wavelength can be located at a large dispersion region, thereby achieving a large group index of 55, an ultra-small effective mode volume of 3.5 × 10 −3 λ 3 , and low-threshold of 11 MW/cm 2 .

We have investigated a hybrid photonic-plasmonic crystal nanocavity consisting of a silicon grating nanowire adjacent to a metal surface with a gain gap between them. The hybrid plasmonic cavity modes are highly confined in the gap due to the strong coupling of the photonic crystal cavity modes and the surface plasmonic gap modes. Using finite-element method (FEM), guided modes of the hybrid plasmonic waveguide (WG) were numerically determined at a wavelength of 1550 nm. The modal characteristics such as WG confinement factors and modal losses of the fundamental hybrid plasmonic modes were obtained as a function of groove depth at various gap heights. Furthermore, the band structure of the hybrid crystal modes corresponding to a wide band gap of 17.8 THz is revealed. To enclose the optical energy effectively, a single defect was introduced into the hybrid crystal. At a deep subwavelength defect length as small as 270 nm, the resonant mode exhibits a high quality factor of 567 and an ultrasmall mode volume of 1.9 × 10 − 3 (λ/n eff) 3 at the resonance wavelength of 1550 nm. Compared to conventional photonic crystal nanowire cavities in the absence of a metal surface, the factor Q/V m is significantly enhanced by about 15 times. The designed hybrid photonic-plasmonic cavity sensors exhibit distinguished characteristics such as sensitivity of 443 nm/RIU and figure of merit of 129. The proposed nanocavities open new possibilities for various applications with strong light-matter interaction, such as biosensors and nanolasers.

In this paper, we investigate several low thermal budget oxide fabrication methods suitable for conventional quartz furnace tube and compare their SiO 2 /SiC interface quality with 1300℃ N 2 O directly oxidized sample. According to the high-low C-V and breakdown test results, we found that the interface quality is still inferior for oxides fabricated below 1200℃, but the dielectric strength is better. Index Terms -Interface state density , silicon carbide.

In this paper, the switching characteristics of Ti/HfO 2 /TiN resistive random access memory (RRAM) have been examined. A novel tunneling barrier width model based on WKB approximation is proposed to explain the pertinent current-voltage characteristic and the origen of the resistance changing in RRAM. It was found that the resistance in high resistance state of RRAM is exponentially related to the reset voltage, and the tunneling barrier width is proportional to the reset voltage. Simulation results show that the TiO x layer formed at the bottom HfO 2 /TiN interface is responsible for the resistance switching. The transient tunnel barrier width changing shows the switching time is related to both ionized charge migration and the redox reaction speed of the conduction filament.

This paper reports a 6-to-18 GHz integrated phasedarray receiver implemented in 130-nm CMOS. The receiver is easily scalable to build a very large-scale phased-array system. It concurrently forms four independent beams at two different frequencies from 6 to 18 GHz. The nominal conversion gain of the receiver ranges from 16 to 24 dB over the entire band while the worst-case cross-band and cross-polarization rejections are achieved 48 dB and 63 dB, respectively. Phase shifting is performed in the LO path by a digital phase rotator with the worst-case RMS phase error and amplitude variation of 0.5 and 0.4 dB, respectively, over the entire band. A four-element phased-array receiver system is implemented based on four receiver chips. The measured array patterns agree well with the theoretical ones with a peak-to-null ratio of over 21.5 dB.

This paper reports a 6-to-18 GHz integrated phasedarray receiver implemented in 130-nm CMOS. The receiver is easily scalable to build a very large-scale phased-array system. It concurrently forms four independent beams at two different frequencies from 6 to 18 GHz. The nominal conversion gain of the receiver ranges from 16 to 24 dB over the entire band while the worst-case cross-band and cross-polarization rejections are achieved 48 dB and 63 dB, respectively. Phase shifting is performed in the LO path by a digital phase rotator with the worst-case RMS phase error and amplitude variation of 0.5 and 0.4 dB, respectively, over the entire band. A four-element phased-array receiver system is implemented based on four receiver chips. The measured array patterns agree well with the theoretical ones with a peak-to-null ratio of over 21.5 dB.

This paper presents a study and design of tunable concurrent dual-band receiver. Different system architectures and building blocks have been compared and analyzed. A tunable concurrent dual-band receiver front end has then been fabricated and characterized. It operates across a tri-tave 6-18 GHz bandwidth with a nominal 17-25 dB conversion gain, worst-case -15 dBm IIP3, and worst-case -24.5 dBm ICP 1 dB.

This investigation explores experimentally the optical characteristics of long-wavelength quantum-dot vertical-cavity surface-emitting lasers (QD VCSELs). The InAs QD VCSEL, fabricated on a GaAs substrate, is grown by molecular beam epitaxy with fully doped distributed Bragg reflectors. The optical characteristics of QD VCSEL without and with light injection are studied in detail. The QD VCSEL has the potential to be used in all-optical signal processing systems.