scholarly journals Effect of Au substrate and coating on the lasing characteristics of GaAs nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gyanan Aman ◽  
Fatemeh Mohammadi ◽  
Martin Fränzl ◽  
Mykhaylo Lysevych ◽  
Hark Hoe Tan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Field Enhancement ◽  
Low Loss ◽  
Band Bending ◽  
Radiative Efficiency ◽  
Polarization Control ◽  
Au Film ◽  
Gaas Nanowires ◽  
On Chip ◽  
Film Substrate

AbstractOptically pumped lasing from highly Zn-doped GaAs nanowires lying on an Au film substrate and from Au-coated nanowires has been demonstrated up to room temperature. The conically shaped GaAs nanowires were first coated with a 5 nm thick Al2O3 shell to suppress atmospheric oxidation and band-bending effects. Doping with a high Zn concentration increases both the radiative efficiency and the material gain and leads to lasing up to room temperature. A detailed analysis of the observed lasing behavior, using finite-difference time domain simulations, reveals that the lasing occurs from low loss hybrid modes with predominately photonic character combined with electric field enhancement effects. Achieving low loss lasing from NWs on an Au film and from Au coated nanowires opens new prospects for on-chip integration of nanolasers with new functionalities including electro-optical modulation, conductive shielding, and polarization control.

scholarly journals Monolithic integrated emitting-detecting configuration based on strained Ge microbridge

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Senbiao Qin ◽  
Junqiang Sun ◽  
Jialin Jiang ◽  
Yi Zhang ◽  
Ming Cheng ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Laser Source ◽  
Strain Variation ◽  
Low Loss ◽  
Temperature Changes ◽  
Monolithically Integrated ◽  
Operating Wavelength ◽  
Cmos Compatible ◽  
On Chip

Abstract The strain technology is accelerating the progress on the CMOS compatible Ge-on-Si laser source. Here, we report a monolithically integrated microbridge-based emitting-detecting configuration, equipped with lateral p–i–n junctions, waveguide and gratings. The operating wavelength range of the emitting bridge and the detecting bridge are matched through the designed same dimensions of the two microbridges, as well as the strain. Strain-enhanced spontaneous emission and the effect of spectra red-shifting on low-loss transmission of on-chip light are discussed. Temperature dependence experiments reveal that in devices with highly strain-enhanced structure, the strain variation can offset the effect of electron thermalization, so that the performance of the device remains stable when temperature changes around room temperature.

scholarly journals Graphene Nanoribbon Gap Waveguides for Dispersionless and Low-Loss Propagation with Deep-Subwavelength Confinement

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1302
Author(s):  
Zhiyong Wu ◽  
Lei Zhang ◽  
Tingyin Ning ◽  
Hong Su ◽  
Irene Ling Li ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Potential ◽  
Shape Change ◽  
Optical Switch ◽  
Pulse Amplitude ◽  
Propagation Distance ◽  
Graphene Nanoribbon ◽  
Low Loss ◽  
High Loss ◽  
On Chip

Surface plasmon polaritons (SPPs) have been attracting considerable attention owing to their unique capabilities of manipulating light. However, the intractable dispersion and high loss are two major obstacles for attaining high-performance plasmonic devices. Here, a graphene nanoribbon gap waveguide (GNRGW) is proposed for guiding dispersionless gap SPPs (GSPPs) with deep-subwavelength confinement and low loss. An analytical model is developed to analyze the GSPPs, in which a reflection phase shift is employed to successfully deal with the influence caused by the boundaries of the graphene nanoribbon (GNR). It is demonstrated that a pulse with a 4 μm bandwidth and a 10 nm mode width can propagate in the linear passive system without waveform distortion, which is very robust against the shape change of the GNR. The decrease in the pulse amplitude is only 10% for a propagation distance of 1 μm. Furthermore, an array consisting of several GNRGWs is employed as a multichannel optical switch. When the separation is larger than 40 nm, each channel can be controlled independently by tuning the chemical potential of the corresponding GNR. The proposed GNRGW may raise great interest in studying dispersionless and low-loss nanophotonic devices, with potential applications in the distortionless transmission of nanoscale signals, electro-optic nanocircuits, and high-density on-chip communications.

scholarly journals Roadmap of Terahertz Imaging 2021

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4092
Author(s):  
Gintaras Valušis ◽  
Alvydas Lisauskas ◽  
Hui Yuan ◽  
Wojciech Knap ◽  
Hartmut G. Roskos
Keyword(s):  
Room Temperature ◽  
Continuous Wave ◽  
Computational Imaging ◽  
Imaging Systems ◽  
Thz Imaging ◽  
Operational Conditions ◽  
Frequency Combs ◽  
Wave Imaging ◽  
On Chip ◽  
Nano Imaging

In this roadmap article, we have focused on the most recent advances in terahertz (THz) imaging with particular attention paid to the optimization and miniaturization of the THz imaging systems. Such systems entail enhanced functionality, reduced power consumption, and increased convenience, thus being geared toward the implementation of THz imaging systems in real operational conditions. The article will touch upon the advanced solid-state-based THz imaging systems, including room temperature THz sensors and arrays, as well as their on-chip integration with diffractive THz optical components. We will cover the current-state of compact room temperature THz emission sources, both optolectronic and electrically driven; particular emphasis is attributed to the beam-forming role in THz imaging, THz holography and spatial filtering, THz nano-imaging, and computational imaging. A number of advanced THz techniques, such as light-field THz imaging, homodyne spectroscopy, and phase sensitive spectrometry, THz modulated continuous wave imaging, room temperature THz frequency combs, and passive THz imaging, as well as the use of artificial intelligence in THz data processing and optics development, will be reviewed. This roadmap presents a structured snapshot of current advances in THz imaging as of 2021 and provides an opinion on contemporary scientific and technological challenges in this field, as well as extrapolations of possible further evolution in THz imaging.

scholarly journals On-chip low loss heralded source of pure single photons

2013 ◽  
Vol 21 (11) ◽  
pp. 13522 ◽  
Author(s):  
Justin B. Spring ◽  
Patrick S. Salter ◽  
Benjamin J. Metcalf ◽  
Peter C. Humphreys ◽  
Merritt Moore ◽  
...  
Keyword(s):  
Single Photons ◽  
Low Loss ◽  
On Chip

Development of 8 mΩ-cm2, 1.8 kV 4H-SiC DMOSFETs

2006 ◽  
Vol 527-529 ◽  
pp. 1261-1264 ◽  
Author(s):  
Sei Hyung Ryu ◽  
Sumi Krishnaswami ◽  
Brett A. Hull ◽  
Bradley Heath ◽  
Mrinal K. Das ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Gate Length ◽  
Gate Bias ◽  
Low Loss ◽  
Layer Resistance ◽  
Switching Characteristics ◽  
Mos Gate ◽  
Drift Layer

8 mΩ-cm2, 1.8 kV power DMOSFETs in 4H-SiC are presented in this paper. A 0.5 μm long MOS gate length was used to minimize the MOS channel resistance. The DMOSFETs were able to block 1.8 kV with the gate shorted to the source. At room temperature, a specific onresistance of 8 mΩ-cm2 was measured with a gate bias of 15 V. At 150 oC, the specific onresistance increased to 9.6 mΩ-cm2. The increase in drift layer resistance due to a decrease in bulk electron mobility was partly cancelled out by the negative shift in MOS threshold voltage at elevated temperatures. The device demonstrated extremely fast, low loss switching characteristics. A significant improvement in converter efficiency was observed when the 4H-SiC DMOSFET was used instead of an 800 V silicon superjunction MOSFET in a simple boost converter configuration.

The Spectral Dependence of the Non-Radiative Efficiency in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
J. Fan ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Free Carrier ◽  
Radiative Efficiency ◽  
Sharp Minimum ◽  
Carrier Thermalization ◽  
Hydrogenated Amorphous ◽  
Kinetics Of ◽  
Heat Released

ABSTRACTThe room temperature non-radiative efficiency, defined as the ratio of the heat released per absorbed photon for doped and undoped hydrogenated amorphous silicon (a-Si:H) has been measured using photo-pyroelectric spectroscopy (PPES) for photon energies ranging from 2.5 to 1.6 eV. There is a fairly sharp minimum in the non-radiative efficiency when the a-Si:H is illuminated with near bandgap photons. We describe a model wherein this minimum arises from the variation in the amount of heat generated by free carrier thermalization as the incident photon energy is varied, and report measurements of the excitation kinetics of the non-radiative efficiency which support this proposal.

High Temperature High Current Gain IC Compatible 4H-SiC Phototransistor

2019 ◽  
Vol 963 ◽  
pp. 832-836 ◽  
Author(s):  
Shuo Ben Hou ◽  
Per Erik Hellström ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
High Temperature ◽  
Integrated Circuits ◽  
Room Temperature ◽  
Uv Light ◽  
Optical Power ◽  
Current Gain ◽  
High Current ◽  
Promising Candidate ◽  
Forward Current ◽  
On Chip

This paper presents our in-house fabricated 4H-SiC n-p-n phototransistors. The wafer mapping of the phototransistor on two wafers shows a mean maximum forward current gain (βFmax) of 100 at 25 °C. The phototransistor with the highest βFmax of 113 has been characterized from room temperature to 500 °C. βFmax drops to 51 at 400 °C and remains the same at 500 °C. The photocurrent gain of the phototransistor is 3.9 at 25 °C and increases to 14 at 500 °C under the 365 nm UV light with the optical power of 0.31 mW. The processing of the phototransistor is same to our 4H-SiC-based bipolar integrated circuits, so it is a promising candidate for 4H-SiC opto-electronics on-chip integration.

LOW LOSS DIELECTRIC MATERIALS FOR HIGH FREQUENCY APPLICATIONS

2009 ◽  
Vol 23 (17) ◽  
pp. 3649-3654 ◽  
Author(s):  
MOHAN V. JACOB
Keyword(s):  
High Frequency ◽  
Room Temperature ◽  
Low Cost ◽  
Dielectric Materials ◽  
Dielectric Constants ◽  
Transmission Losses ◽  
Low Loss ◽  
Microwave Characterization ◽  
Materials Used ◽  
Low Temperature Electronics

The microwave properties of some of the low cost materials which can be used in high frequency applications with low transmission losses are investigated in this paper. One of the most accurate microwave characterization techniques, Split Post Dielectric Resonator technique (SPDR) is used for the experimental investigation. The dielectric constants of the 3 materials scrutinized at room temperature and at 10K are 3.65, 2.42, 3.61 and 3.58, 2.48, 3.59 respectively. The corresponding loss tangent values are 0.00370, 0.0015, 0.0042 and 0.0025, 0.0009, 0.0025. The high frequency transmission losses are comparable with many of the conventional materials used in low temperature electronics and hence these materials could be implemented in such applications.

Sign in / Sign up

Export Citation Format

Share Document