Low Frequency Noise of Carbon Nanotubes THz detectors

We report studies of noise properties of carbon nanotube (CNT) networks-based devices used for the terahertz detectors. Low-frequency noise characteristics of CNTs as a function of temperature, UV illumination, and back-gate voltages were examined. Our results demonstrated the existence of at least two important resistance components of nanotubes rather than generally accepted dominant tube-to-tube junction resistance. We showed that noise spectroscopy can be employed to probe the structural quality of nanotube networks. Measurements as a function of back gate voltages revealed the existence of generation-recombination noise, related to deep tarps, which play a significant role in the performances of CNT networks-based terahertz detectors.QC 20211215</p

Low-frequency noise in Au-decorated graphene-Si Schottky barrier diode at selected ambient gases

We report results of the current-voltage characteristics and low-frequency noise in Au nanoparticle (AuNP)-decorated graphene-Si Schottky barrier diodes. Measurements were conducted in ambient air with addition of either of two organic vapors, tetrahydrofuran [(CH2)(4)O; THF] and chloroform (CHCl3), as also during yellow light illumination (592 nm), close to the measured particle plasmon polariton frequency of the Au nanoparticle layer. We observed a shift of the DC characteristics at forward voltages (forward resistance region) when tetrahydrofuran vapor was admitted (in a Au-decorated graphene-Si Schottky diode), and a tiny shift under yellow irradiation when chloroform was added (in not decorated graphene-Si Schottky diode). Significantly larger difference in the low-frequency noise was observed for the two gases during yellow light irradiation, compared with no illumination. The noise intensity was suppressed by AuNPs when compared with noise in graphene-Si Schottky diode without an AuNP layer. We conclude that flicker noise generated in the investigated Au-decorated Schottky diodes can be utilized for gas detection

Passive Photonic Integrated Circuits Elements Fabricated on a Silicon Nitride Platform

The fabrication processes for silicon nitride photonic integrated circuits evolved from microelectronics components technology—basic processes have common roots and can be executed using the same type of equipment. In comparison to that of electronics components, passive photonic structures require fewer manufacturing steps and fabricated elements have larger critical dimensions. In this work, we present and discuss our first results on design and development of fundamental building blocks for silicon nitride integrated photonic platform. The scope of the work covers the full design and manufacturing chain, from numerical simulations of optical elements, design, and fabrication of the test structures to optical characterization and analysis the results. In particular, technological processes were developed and evaluated for fabrication of the waveguides (WGs), multimode interferometers (MMIs), and arrayed waveguide gratings (AWGs), which confirmed the potential of the technology and correctness of the proposed approach