On-chip filter bank spectroscopy at 600–700?GHz using NbTiN superconducting resonators

We experimentally demonstrate the principle of an on-chip submillimeter wave filter bank spectrometer, using superconducting microresonators as narrow band-separation filters. The filters are made of NbTiN/SiNx/NbTiN microstrip line resonators, which have a resonance frequency in the range of 614-685?GHz, two orders of magnitude higher in...

Operation of a titanium nitride superconducting microresonator detector in the nonlinear regime

If driven sufficiently strongly, superconducting microresonators exhibit nonlinear behavior including response bifurcation. This behavior can arise from a variety of physical mechanisms including heating effects, grain boundaries or weak links, vortex penetration, or through the intrinsic nonlinearity of the kinetic inductance. Although...

Characterization of low temperature deposited atomic layer deposition TiO2 for MEMS applications

TiO2 is an interesting and promising material for micro-/nanoelectromechanical systems (MEMS/NEMS). For high performance and reliable MEMS/NEMS, optimization of the optical characteristics, mechanical stress, and especially surface smoothness of TiO2 is required. To overcome the roughness issue of the TiO2 films due to crystallization during...

Homogeneous superconducting phase in TiN film: A complex impedance study

The low frequency complex impedance of a high resistivity 92?????cm and 100?nm thick TiN superconducting film has been measured via the transmission of several high sensitivity GHz microresonators, down to TC/50. The temperature dependence of the kinetic inductance follows closely BCS local electrodynamics, with one well defined superconducting...

Critical-current reduction in thin superconducting wires due to current crowding

We demonstrate experimentally that the critical current in superconducting NbTiN wires is dependent on their geometrical shape, due to current-crowding effects. Geometric patterns such as 90? corners and sudden expansions of wire width are shown to result in the reduction of critical currents. The results are relevant for single-photon detectors...

Titanium nitride: A new Ohmic contact material for n-type CdS

In devices based on CdS, indium is often used to make Ohmic contacts. Since indium is scarce and expensive, suitable replacement materials need to be found. In this work, we show that sputtered titanium nitride forms an Ohmic contact with n-type CdS. The CdS films, deposited with chemical bath deposition, have a hexagonal crystal structure and...

Reduced frequency noise in superconducting resonators

We report a reduction in the frequency noise in coplanar waveguide superconducting resonators. The reduction of 7 dB is achieved by removing the exposed dielectric substrate surface from the region with high electric fields and by using NbTiN. In a model-analysis the surface of NbTiN is found to be a negligible source of noise, experimentally...

Enhanced telecom wavelength single-photon detection with NbTiN superconducting nanowires on oxidized silicon

Superconducting nanowire single-photon detectors (SNSPDs) have emerged as a highly promising infrared single-photon detector technology. Next-generation devices are being developed with enhanced detection efficiency (DE) at key technological wavelengths via the use of optical cavities. Furthermore, new materials and substrates are being explored...

Lithium Storage in Amorphous TiO2 Nanoparticles

Amorphous titanium oxide nanoparticles were prepared from titanium isopropoxide. In situ measurements reveal an extraordinary high capacity of 810 mAh/g on the first discharge. Upon cycling at a charge/discharge rate of 33.5 mA/g, this capacity gradually decreases to 200 mAh/g after 50 cycles. The origin of this fading was investigated using X...

Time-of-flight studies on TiO2/CuInS2 heterojunctions

Time-of-Flight (TOF) measurements have been performed on n-type TiO2/p-type CuInS2 heterojunctions. The TiO2 film thickness has been varied between 200 and 400 nm, while the CuInS2 film thickness has been fixed at 500 nm. The TOF response can be accurately modeled, if the potential drop across the p-n heterojunction with a large density of...

A time-resolved microwave conductivity study of the optoelectronic processes in TiO2?In2S3?CuInS2 heterojunctions

Photoinduced interfacial charge carrier generation, separation, trapping, and recombination in TiO2?In2S3?CuInS2 cells have been studied with time-resolved microwave conductivity (TRMC). Single layer, double layer, and complete triple layer configurations have been studied. Selective electronic excitation in one of the components is accomplished...

Deep-level transient spectroscopy of TiO2/CuInS2 heterojunctions

Deep-level transient spectroscopy (DLTS) has been used to measure the concentration and energy position of deep electronic states in CuInS2. Flat TiO2?CuInS2 heterojunctions as well as TiO2-CuInS2 nanocomposites have been investigated. Subband-gap electronic states in CuInS2 films are mostly due to antisite point defects and vacancies....

Niobium titanium nitride-based superconductor-insulator-superconductor mixers for low-noise terahertz receivers

Integrating NbTiN-based microstrip tuning circuits with traditional Nb superconductor-insulator-superconductor (SIS) junctions enables the low-noise operation regime of SIS mixers to be extended from below 0.7?to?1.15?THz. In particular, mixers incorporating a NbTiN/SiO2/NbTiN microstrip tuning circuit offer low-noise performance below 0.8–0.85...

Enhanced photoluminescence at poly(3-octyl-thiophene)/TiO2 interfaces

The photoluminescence (PL) of poly(3-octyl-thiophene) (P3OT) thin films applied on TiO2 substrates is compared to the PL of P3OT films applied on quartz. Quenching of excitons occurs at the P3OT/TiO2 interface and not at the P3OT/quartz interface. Yet, in the former case the PL intensity is stronger than in the latter. In particular, P3OT films...