共查询到20条相似文献,搜索用时 15 毫秒
1.
Dieter Schmeißer Günter Appel Oliver Bhme Thomas Heller Ricardo P. Mikalo Patrick Hoffmann David Batchelor 《Sensors and actuators. B, Chemical》2000,70(1-3):131-138
The spectroscopic characterization of localized charges in thin film devices is addressed. We demonstrate their existence and show their particular contribution to the operation of sensor devices. Examples in oxidic and polymeric thin films systems are given in which the localized states dominate the electronic properties. 相似文献
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The mobility limiting scattering mechanisms for amorphous semiconductors and polar polycrystalline semiconductors are studied in the context of developing new high‐performance thin‐film transistor (TFT) channel layer materials for large‐area electronics. A physics‐based model for carrier transport in an amorphous semiconductor is developed to estimate the mobility limits of amorphous semiconductor TFTs. The model involves band tail state trapping of a diffusive mobility. Simulation reveals a strong dependence on the band tail density of states. This consideration makes it difficult to realize a high‐performance p‐type oxide TFT. A polar crystalline semiconductor may offer a higher mobility but is fundamentally limited by polar optical phonon scattering. Any crystalline TFT channel layer for practical large‐area applications will not be a single crystal but polycrystalline, and therefore, grain size and grain boundary‐dependent scattering will further degrade the transport properties. 相似文献
3.
薄膜热电偶温度传感器研究进展 总被引:1,自引:0,他引:1
随着低维材料技术的发展和对测温要求的提高,薄膜热电偶温度传感器应运而生,其快速响应特性为测量瞬变温度提供了可能。综述了薄膜热电偶温度传感器国内外发展现状,着重介绍了薄膜临界厚度的确定、扩散现象的影响、制备工艺等关键技术,并对其未来发展做出了展望。 相似文献
4.
Hongyi QinAuthor Vitae Atul Kulkarni Hang ZhangHojoong Kim Dong JiangTaesung KimAuthor Vitae 《Sensors and actuators. B, Chemical》2011,158(1):223-228
A fiber optic reflectance sensor (FORS) using Polypyrrole (PPy) conducting polymer to detect volatile organic compounds (VOCs) is demonstrated. The conventional interfacial polymerization method is used to synthesize a sensitive polypyrrole membrane, which shows relatively low roughness and high reflectivity. In general the changes in electrical properties of conductive polymers are explored in sensing applications, however their optical properties have been less explored. In the present study, we evaluate the optical properties of PPy and transfer on the end face of polymer optical fiber (POF) for the detection of VOCs. The change in the reflected optical signal from PPy upon interaction with the VOCs is systematically evaluated. The fabricated PPy FORS shows the excellent sensitivity to the VOCs under test with the detection limit up to 1 ppm. 相似文献
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Ye AiAuthor VitaeJing LiuAuthor Vitae Bingkai ZhangAuthor VitaeShizhi QianAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):742-751
A conical nanofluidic field effect transistor (FET) refers to a conical nanopore embedded with an electrically controllable gate electrode. The surface potential of the nanopore can be effectively regulated by manipulating the gate potential applied to the gate electrode, which in turn controls the ionic current through the nanopore. The field effect on the ionic current rectification (ICR) in the conical nanofluidic FET is comprehensively investigated using a continuum model, composed of Nernst-Planck equations for the ionic concentrations, Poisson equation for the electric potential, and Navier-Stokes equations for the flow field. Under the conditions of a low ionic concentration, a low surface charge density of the nanopore, and a high permittivity of the dielectric nanopore, regulation of ICR by FET is significant. The field effect on the ICR with the gate electrode located in the middle region is opposite to that with the gate electrode located near the tip of the nanopore. 相似文献
7.
Bill Denson 《Journal of the Society for Information Display》2015,23(3):91-96
Electrostatic discharge (ESD) is a significant cause of yield loss in thin‐film transistor (TFT) array manufacturing. TFT arrays are at increased risk relative to other electronic components because the TFTs are unprotected; the array has a large inherent capacitance, and TFT processing includes many chucking and conveyance steps that result in triboelectric charge generation. To reduce or eliminate ESD‐caused fallout, an understanding must be gained of an ESD event's fundamental physics, including the mechanism of charge generation, ESD event physics, and TFT failure modes. An equivalent circuit model has been developed to address the physics of how ESD events occur. The ESD event scenarios modeled with this circuit are as follows: (1) the substrate glass is lifted from the chuck, resulting in a non‐uniform static charge; (2) this charge induces a voltage on the A‐side components; (3) the substrate is lifted, causing a voltage increases; (4) the uneven charge generated results in voltage gradients between TFTs, resulting in an ESD event. This model combines the effects of TFT substrate lifting and charge generation, with a simplified equivalent circuit representing the TFT array. The behavior of this circuit was simulated with a spice model (Electronics Research Laboratory of the University of California, Berkeley, CA, USA.) to characterize the ESD pulse. 相似文献
8.
Chan Woo ParkAuthor Vitae Chil Seong AhAuthor VitaeChang-Geun AhnAuthor Vitae Jong-Heon YangAuthor VitaeAnsoon KimAuthor Vitae Tae-Youb KimAuthor VitaeGun Yong Sung Author Vitae 《Sensors and actuators. B, Chemical》2011,154(2):164-168
We demonstrate the application of ‘top-down’ fabricated Si nanochannel field effect transistor biosensors for measuring charging properties or configuration of proteins immobilized on the Si surface. We have immobilized monoclonal antibodies for prostate specific antigen (anti-PSA) on the p-type Si channel surface, and monitored the channel conductance in response to the variation of ionic strength (salt concentration) and pH of the buffer solution. Effects of the salt concentration at a constant pH is consistent with the screening of protein charges by dissolved counter-ions, enabling analysis of the net protein charge and spatial configuration based on calculated values of Debye screening length (λD). The pH-dependence of channel conductance at varying salt concentration has also been investigated, from which the relationship between the pH and net protein charge can be estimated. 相似文献
9.
A new subject‐specific course on thin‐film transistor (TFT) circuit design is introduced, covering related knowledge of display technologies, TFT device physics, processing, characterization, modeling and circuit design. A design project is required for students to deepen the understanding even more and get hands‐on design experience. This course can be an intense 1‐week course to offer a full training of design engineers in an organized way to meet the ever‐increasing needs in display industry for TFT circuit design specialists. It can also be organized in one semester for electrical engineering Master's and Ph.D. students. 相似文献
10.
The realization and applicability of a new dynamic hydrogen reference electrode (DHRE) within an electrochemical microcell for sensor applications is reported. The electrodes are fabricated in thin-film technology and fixed within a flow-through device. An experimental setup for accurate electrochemical potential measurements is described. Smooth platinum, platinized platinum and pHEMA coated electrodes are investigated with regard to their initialization behavior, stability, reproducibility and interference with electrolytes. It is found that platinized platinum DHREs show excellent stability and reproducibility. For uncoated electrodes, the electrochemical potential is established within seconds. The potential is independent of the pH value within the range of pH 4–10. Interference with sulfate and phosphate is observed. Thus, the platinized platinum DHRE is well suited for bioanalytical sensor applications, where the pH value is buffered and the concentrations of the disturbing anions are constant or very low. 相似文献
11.
A compact, differential, hydrogen-specific sensor based on the lattice expansion of LaAl0.3Ni4.7 metal hydride thin films has been fabricated and characterized. Characterization of LaAl0.3Ni4.7 films performed using a capacitance dilatometer revealed that the lattice expansion was proportional to the partial pressure of H2 over the range 0.01–1.3 atm used in this experiment. The films were mechanically robust to cycling between vacuum and partial pressures of H2 up to 1.3 atm and were not poisoned by exposure to atmosphere's containing up to 24% carbon monoxide. A wafer level process has been established for the fabrication of the differential hydrogen sensor which includes both an active LaAl0.3Ni4.7 sensing capacitor and an inert Au reference capacitor. A minimum sensitivity of 400 ppm hydrogen is calculated for the differential device. 相似文献
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E. Momoniat 《Computers & Mathematics with Applications》2011,62(1):383-391
A shooting method is used to determine a solution to a third-order ODE modeling the steady profile of a non-Newtonian thin droplet. We compare a direct approach to an iterative approach using a secant method. We obtain a nonlinear relationship between the contact angle ? and the position of the contact line r. From this nonlinear relationship we use curve fitting to obtain an empirical law of the form tan?∝rf(k) where k is the power law coefficient and f is a nonlinear function of k. 相似文献
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Atomistic simulations of thin film deposition, based on the lattice Monte Carlo method, provide insights into the microstructure evolution at the atomic level. However, large-scale atomistic simulation is limited on a single computer—due to memory and speed constraints. Parallel computation, although promising in memory and speed, has not been widely applied in these simulations because of the intimidating overhead. The key issue in achieving optimal performance is, therefore, to reduce communication overhead among processors. In this paper, we propose a new parallel algorithm for the simulation of large-scale thin film deposition incorporating two optimization strategies: (1) domain decomposition with sub-domain overlapping and (2) asynchronous communication. This algorithm was implemented both on message-passing-processor systems (MPP) and on cluster computers. We found that both architectures are suitable for parallel Monte Carlo simulation of thin film deposition in either a distributed memory mode or a shared memory mode with message-passing libraries. 相似文献
16.
J. RaviPrakash A.H. McDaniel M. Horn L. Pilione P. Sunal R. Messier R.T. McGrath F.K. Schweighardt 《Sensors and actuators. B, Chemical》2007,120(2):439-446
The effect of thin film morphology, carbon monoxide (CO) and resistor geometry on the response of hydrogen sensitive thin film palladium resistors has been investigated. Films with two different morphologies were fabricated by DC magnetron sputtering under different gas pressures. Palladium thin film morphology was found to strongly influence sensor response in terms of hydrogen sensitivity and rate of response. In dense columnar Pd films, CO dramatically increases the time-lag in sensor response to H2 in H2/CO mixtures. However, the steady state value of the response remains unchanged. Films with a void filled columnar morphology exhibited shorter time-lag in response to H2 in presence of CO. 相似文献
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James E. RoyerAuthor VitaeSangyeob LeeAuthor Vitae Charlene ChenAuthor VitaeByungmin AhnAuthor Vitae William C. TroglerAuthor VitaeJerzy KanickiAuthor Vitae Andrew C. KummelAuthor Vitae 《Sensors and actuators. B, Chemical》2011,158(1):333-339
Organic thin film transistor (OTFT) chemical sensors rely on the specific electronic structure of the organic semiconductor (OSC) film for determining sensor stability and response to analytes. The delocalized electronic structure is influenced not only by the OSC molecular structure, but also the solid state packing and film morphology. Phthalocyanine (H2Pc) and tetrabenzoporphyrin (H2TBP) have similar molecular structures but different film microstructures when H2Pc is vacuum deposited and H2TBP is solution deposited. The difference in electronic structures is evidenced by the different mobilities of H2TBP and H2Pc OTFTs. H2Pc has a maximum mobility of 8.6 × 10−4 cm2 V−1 s−1 when the substrate is held at 250 °C during deposition and a mobility of 4.8 × 10−5 cm2 V−1 s−1 when the substrate is held at 25 °C during deposition. Solution deposited H2TBP films have a mobility of 5.3 × 10−3 cm2 V−1 s−1, which is consistent with better long-range order and intermolecular coupling within the H2TBP films compared to the H2Pc films. Solution deposited H2TBP also exhibits a textured film morphology with large grains and an RMS roughness 3-5 times larger than H2Pc films with similar thicknesses. Despite these differences, OTFT sensors fabricated from H2TBP and H2Pc exhibit nearly identical analyte sensitivity and analyte response kinetics. The results suggest that while the interactions between molecules in the solid state determine conductivity, localized interactions between the analyte and the molecular binding site dominate analyte binding and determine sensor response. 相似文献
19.
The evaporating thin film region is an extended meniscus beyond the apparent contact line at a liquid/solid interface. Thin
film evaporation plays a key role in a highly efficient heat pipe. A detailed mathematical model predicting fluid flow and
heat transfer through the thin film region is developed. The model considers the effects of inertial force, disjoining pressure,
surface tension, and curvature. Utilizing the order analysis, the model is simplified and can be numerically solved for the
thin film profile, interfacial temperature, meniscus radius, heat flux distribution, velocity distribution, and mass flow
rate in the evaporating thin film region. The prediction shows that while the inertial force can affect the thin film profile,
interfacial temperature, meniscus radius, heat flux distribution, velocity distribution, and mass flow rate, in particular,
near the non-evaporating region, the effect can be neglected. It is found that a maximum velocity, a maximum heat flux, and
a maximum curvature exist for a given superheat, but the locations for these maximum values are different. 相似文献
20.
SeonYeob Young-Geun Sungwon Hong-Seok Seong-Min 《Sensors and actuators. B, Chemical》2007,120(2):368-377
The corrosion sensor should have high sensitivity enough to measure the corrosion rate in mild corrosive environments and the ability to detect the corrosion mechanism. Therefore, our goal is to develop and apply a steel thin film electrical resistance (TFER) sensor based on the measurement of changes in electrical resistance of the sensing elements in order to follow the corrosion of steel in a wide range of environments. The sensor with a thickness of 600 nm is fabricated by DC magnetron sputter deposition of steel on an Al2O3 substrate, followed by silk screen printing to improve the sensitivity of the sensor, especially to measure the corrosion rate in low corrosive environments such as anoxic corrosion in neutral solutions, steel protected by protective measures like a corrosion inhibitor or cathodic protection, and atmospheric corrosion. The sensor also has multiple-line sensing elements to detect the localized corrosion of steel. The TFER sensor is laboratory and field tested. All the studies demonstrate that the newly developed TFER sensor can be a promising and reliable tool for corrosion monitoring of steel exposed to various environments. 相似文献