The Experts below are selected from a list of 127233 Experts worldwide ranked by ideXlab platform
Yicheng Wang - One of the best experts on this subject based on the ideXlab platform.
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ion energy distributions in inductively coupled radio frequency discharges in argon nitrogen oxygen chlorine and their mixtures
Journal of Applied Physics, 1999Co-Authors: Yicheng Wang, James K OlthoffAbstract:We report ion energy distributions, relative ion intensities, and absolute total ion current densities at the grounded electrode of an inductively coupled Gaseous Electronics Conference radio-frequency Reference Cell for discharges generated in pure argon, nitrogen, oxygen, and chlorine, and in mixtures of argon with N2, O2, and Cl2. Measured current densities are significantly greater for pure argon and for mixtures containing argon than for pure N2, O2, and Cl2. For all three molecular gases, the ratio of molecular ions to the fragment ions decreases when argon is added to the molecular gas discharges. A possible destruction mechanism for the molecular ions involving metastable argon is discussed.
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radio frequency voltage division between two plasma sheaths in the gaseous electronics conference Reference Cell
Applied Physics Letters, 1995Co-Authors: Yicheng WangAbstract:A new method is described for calculating the rf voltage division between two plasma sheaths in the capacitively coupled asymmetric Gaseous Electronics Conference Reference Cell, where the effective area ratio of the electrodes is unknown. The rf voltage across the ground sheath is found to decrease with increasing total electrode rf voltage, indicating that the effective area of the ground electrode increases significantly.
Luis Echegoyen - One of the best experts on this subject based on the ideXlab platform.
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enhanced open circuit voltage in perovskite solar Cells with open cage 60 fullerene derivatives as electron transporting materials
Materials, 2019Co-Authors: Edison Castro, Albert Artigas, Anna Plaquintana, Anna Roglans, Fang Liu, Frank G Perez, Agusti Lledo, X Y Zhu, Luis EchegoyenAbstract:The synthesis, characterization, and incorporation of open-cage [60]fullerene derivatives as electron-transporting materials (ETMs) in perovskite solar Cells (PSCs) with an inverted planar (p-i-n) structure is reported. Following optical and electrochemical characterization of the open-cage fullerenes 2a–c, p-i-n PSCs with a indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS)/perovskite/fullerene/Ag structure were prepared. The devices obtained from 2a–b exhibit competitive power conversion efficiencies (PCEs) and improved open-circuit voltage (Voc) values (>1.0 V) in comparison to a Reference Cell based on phenyl-C61-butyric-acid methyl-ester (PC61BM). These results are rationalized in terms of a) the higher passivation ability of the open-cage fullerenes with respect to the other fullerenes, and b) a good overlap between the highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) levels of 2a–b and the conduction band of the perovskite.
B O Fimland - One of the best experts on this subject based on the ideXlab platform.
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positioning effects on quantum dot solar Cells grown by molecular beam epitaxy
Applied Physics Letters, 2010Co-Authors: D Zhou, Per Erik Vullum, G Sharma, Sedsel Fretheim Thomassen, Randi Holmestad, Turid Worren Reenaas, B O FimlandAbstract:We report current-voltage and spectral response characteristics of high density InAs/GaAs quantum dot (QD) solar Cells with different positions where dots are located. The short circuit current density (Jsc), open circuit voltage (Voc), and external quantum efficiency of these Cells under air mass 1.5 are presented and compared with a GaAs Reference Cell. An extended photoresponse in contrast to the GaAs Reference Cell was confirmed for all these Cells. The effect of inserting QD layers into emitter and base region on device performance is shown. The Jsc is reduced, while the Voc is maintained. The Cell with QDs located toward the base side shows better performance, confirmed by both current-voltage and spectral response measurements.
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optimization towards high density quantum dots for intermediate band solar Cells grown by molecular beam epitaxy
Applied Physics Letters, 2010Co-Authors: D Zhou, G Sharma, Sedsel Fretheim Thomassen, Turid Worren Reenaas, B O FimlandAbstract:We report high density quantum dots (QDs) formation with optimized growth temperature and V/III ratio. At lower growth temperature, QD density is increased, due to smaller surface migration length of In adatoms. With higher V/III, the QD density is higher but it results in large clusters formation and decreases the QD uniformity. The QD solar Cell was fabricated and examined. An extended spectral response in contrast to the GaAs Reference Cell was presented but the external quantum efficiency at energies higher than GaAs band gap is reduced, resulting from the degradation for the emitter above the strained QD layers.
Herbert H Sawin - One of the best experts on this subject based on the ideXlab platform.
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ion energy and angular distributions in inductively coupled radio frequency discharges in argon
Journal of Applied Physics, 1996Co-Authors: J R Woodworth, Merle E Riley, Dorothy C Meister, B P Aragon, Herbert H SawinAbstract:We report measurements of the energies and angular distributions of positive ions in an inductively coupled argon plasma in a Gaseous Electronics Conference Reference Cell. Use of two separate ion detectors allowed measurement of ion energies and fluxes as a function of position as well as ion angular distributions on the discharge centerline. The inductive drive on our system produced high plasma densities (up to 1012/cm3 electron densities) and relatively stable plasma potentials. As a result, ion energy distributions typically consisted of a single feature well separated from zero energy. Mean ion energy was independent of rf power and varied inversely with pressure, decreasing from 29 to 12 eV as pressure increased from 2.4 to 50 mTorr. The half‐widths of the ion angular distributions in these experiments varied from 5° to 9°, or equivalently, the transverse temperatures varied from 0.18 to 0.29 eV with the distributions broadening as either pressure or rf power was increased.
James K Olthoff - One of the best experts on this subject based on the ideXlab platform.
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ion energy distributions in inductively coupled radio frequency discharges in argon nitrogen oxygen chlorine and their mixtures
Journal of Applied Physics, 1999Co-Authors: Yicheng Wang, James K OlthoffAbstract:We report ion energy distributions, relative ion intensities, and absolute total ion current densities at the grounded electrode of an inductively coupled Gaseous Electronics Conference radio-frequency Reference Cell for discharges generated in pure argon, nitrogen, oxygen, and chlorine, and in mixtures of argon with N2, O2, and Cl2. Measured current densities are significantly greater for pure argon and for mixtures containing argon than for pure N2, O2, and Cl2. For all three molecular gases, the ratio of molecular ions to the fragment ions decreases when argon is added to the molecular gas discharges. A possible destruction mechanism for the molecular ions involving metastable argon is discussed.
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electrical sensors for monitoring rf plasma sheaths
Microelectronic Processes Sensors and Controls, 1994Co-Authors: Mark A Sobolewski, James K OlthoffAbstract:We have investigated the use of radio-frequency (rf) current and voltage measurements to monitor the electrical characteristics of rf plasmas and to predict changes in ion kinetic energy distributions. These studies were performed at 2.7 and 13.3 Pa (20 and 100 mTorr) in a Gaseous Electronics Conference RF Reference Cell in mixtures of argon with oxygen, nitrogen and water. It is expected that the measurement techniques described here could be extended to monitor the sheath above a wafer during plasma etching to obtain information about changes in the condition of the wafer surface and the energies of ions bombarding it.