Photo-ionization efficiency curves of alkali nanoclusters in a beam and determination of metal work functions

2001 ◽  
Vol 73 (4) ◽  
pp. 407-410 ◽  
Author(s):  
K. Wong ◽  
V. Kasperovich ◽  
G. Tikhonov ◽  
V.V. Kresin
Keyword(s):  
Ionization Efficiency ◽  
Work Functions ◽  
Photo Ionization ◽  
Metal Work

Barrier heights of Schottky contacts on strained AlGaN/GaN heterostructures: Determination and effect of metal work functions

2003 ◽  
Vol 82 (24) ◽  
pp. 4364-4366 ◽  
Author(s):  
Zhaojun Lin ◽  
Wu Lu ◽  
Jaesun Lee ◽  
Dongmin Liu ◽  
Jeffrey S. Flynn ◽  
...  
Keyword(s):  
Schottky Contacts ◽  
Barrier Heights ◽  
Work Functions ◽  
Metal Work

scholarly journals Determination of the absorption cross-sections of higher order iodine oxides at 355 nm and 532 nm

2020 ◽  
Author(s):  
Thomas R. Lewis ◽  
Juan Carlos Gómez Martin ◽  
Mark A. Blitz ◽  
Carlos A. Cuevas ◽  
John M. C. Plane ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Atmospheric Chemistry ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Time Resolved ◽  
Flight Mass Spectrometry ◽  
Iodine Oxides ◽  
Photo Ionization

Abstract. Iodine oxides (IxOy) play an important role in the atmospheric chemistry of iodine. They are initiators of new particle formation events in the coastal and polar boundary layer and act as iodine reservoirs in tropospheric ozone-depleting chemical cycles. Despite the importance of the aforementioned processes, the photochemistry of these molecules has not been studied in detail previously. Here, we report the first determination of the absorption cross sections of IxOy, x = 2, 3, 5, y = 1–12 at λ = 355 nm by combining pulsed laser photolysis of I2/O3 gas mixtures in air with time-resolved photo-ionization time-of-flight mass spectrometry, using NO2 actinometry for signal calibration. The oxides selected for absorption cross section determinations are those presenting the strongest signals in the mass spectra, where signals containing 4 iodine atoms are absent. The method is validated by measuring the absorption cross section of IO at 355 nm, σ355 nm, IO = (1.2 ± 0.1) ×  10–18 cm2, which is found to be in good agreement with the most recent literature. The results obtained are: σ355 nm, I2O3 

Influence of cathode material type on the electrical breakdown behaviors of DC discharge

2020 ◽  
Vol 98 (8) ◽  
pp. 726-731
Author(s):  
F. Diab ◽  
W.H. Gaber ◽  
M.E. Abdel-kader ◽  
B.A. Soliman ◽  
M.A. Abd Al-Halim
Keyword(s):  
Cathode Material ◽  
Work Function ◽  
Breakdown Voltage ◽  
Cathode Materials ◽  
Electrical Breakdown ◽  
Ionization Efficiency ◽  
Parallel Plates ◽  
Maximum Value ◽  
Dc Discharge ◽  
Work Functions

Paschen curves were studied using different cathode materials such as magnesium, zinc, and carbon graphite by discharge in argon gas of a pressure range between 0.08 and 3 Torr using a parallel plates configuration. The first and second Townsend coefficients (α and γ, respectively) and the ionization efficiency (η) of different cathode materials were deduced from Paschen curves as a function of the reduced field (E/P). The minimum breakdown voltage was found to be about 242 V for Mg material, which has the lowest work function, while carbon graphite has a higher breakdown voltage of 283 V due to its higher work function. The second coefficient γ was increased as a function of E/P and has higher values for materials of lower work functions, and a similar trend of γ is obtained as a function of the ion mean energy. On the other hand, the first coefficient α has a reverse behavior with both E/P and the work function of the cathode materials compared with the second coefficient. The ionization efficiency of the three cathode materials is identical, as η depends only on the gas properties and not the cathode material. η has a maximum value of about 0.025 V−1 for an E/P of about 185 Vcm−1Torr−1, corresponding to the maximum ionizing ability of electrons. The validation of the breakdown results has been confirmed by conferring with other published experimental measurements.

Trap-assisted tunnelling current in MIM structures

Open Physics ◽  
2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Juraj Racko ◽  
Miroslav Mikolášek ◽  
Ralf Granzner ◽  
Juraj Breza ◽  
Daniel Donoval ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Quantum Mechanical ◽  
Current Transport ◽  
Metal Insulator ◽  
Insulating Layer ◽  
New Model ◽  
Metal Insulator Metal ◽  
Work Functions ◽  
Metal Work ◽  
Tunnelling Current

AbstractA new model is presented of current transport in Metal Insulator Metal (MIM) structures by quantum mechanical tunnelling. In addition to direct tunnelling through an insulating layer, tunnelling via defects present in the insulating layer plays an important role. Examples of the influence of the material and thickness of the insulating layer, energy distribution of traps, and metal work functions are also provided.

scholarly journals Tuning of Metal Work Functions with Self-Assembled Monolayers

2005 ◽  
Vol 17 (5) ◽  
pp. 621-625 ◽  
Author(s):  
B. de Boer ◽  
A. Hadipour ◽  
M. M. Mandoc ◽  
T. van Woudenbergh ◽  
P. W. M. Blom
Keyword(s):  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Work Functions ◽  
Self Assembled ◽  
Metal Work

Influence of Metal Electrodes on the Ferroelectric Responses of Poly(vinylidene fluoride-trifluoroethylene) Copolymer Thin Films

2002 ◽  
Vol 734 ◽  
Author(s):  
Feng Xia ◽  
Q. M. Zhang
Keyword(s):  
Thin Films ◽  
Vinylidene Fluoride ◽  
Bias Field ◽  
Polarization Switching ◽  
Interface Effect ◽  
Metal Electrodes ◽  
Poly Vinylidene Fluoride ◽  
Work Functions ◽  
Metal Work ◽  
Bulk Effect

ABSTRACTFerroelectric polymer thin films have been investigated for applications such as sensors, MEMS, and memory devices, just name a few. In these thin film devices, it is anticipated that the interface effect will play an important role in determining the device performance. In this paper, we present the results of a recent study on the influence of metal electrodes on ferroelectric switching behavior of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) polymer thin films. The results show that the influence of metal electrodes on the polarization response can be divided into two effects, the bulk effect and interface effect. The bulk effect manifests itself as the built-in bias field when metal electrodes with different work functions were used on the two surfaces of the P(VDF-TrFE) film. The interface effect is more complicated but is directly related to the metal work function. For a metal I/insulator (ferroelectric film)/metal II (MIM) sandwich structure in which the metal I and metal II possess different work functions, the low frequency polarization hysteresis loop shows asymmetric response (different switching fields). The polarization switching time also depends on whether the applied voltage is in parallel or anti-parallel to the built-in bias field. In the fast polarization switching process, it was observed that the interface effect plays a dominating role and the switching time is mainly limited by the charge injection from metal electrodes to the polymer film. For metal electrodes with higher work function, higher injection currents and hence faster polarization switching were observed. The results from I-V studies also show that the charge injection process is a Schottky type and the barrier height estimated from the temperature dependence of the I-V curves is consistent with the metal work functions used.

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