Steady State Photocarrier Charge Collection in a-Si:H for Electrons and Holes

1991 ◽  
Vol 219 ◽  
Author(s):  
C.-D. Abel ◽  
H. R. Paes ◽  
G. H. Bauer
Keyword(s):  
Steady State ◽  
Amorphous Silicon ◽  
Carrier Transport ◽  
Room Temperature ◽  
Charge Collection ◽  
Electron Charge ◽  
Extended State ◽  
Pin Diodes ◽  
Temperature Electron ◽  
Generation Region

AbstractCarrier transport in amorphous silicon pin-diodes has been analyzed by steady state photocarrier charge collection applying strongly absorbed light. For low intensities at room temperature electron charge collection is limited by recombination in the generation region. For increasing intensity ø and/or decreasing temperature charge collection becomes nonlinear in ø and shows S-like characteristics versus voltage.We present a model for this behaviour, including space charge limitation which e.g. for holes in a-Si:H limits charge collection even at room temperature due to low extended state mobility of holes and dark Fermi level position above midgap.

The Study of Space Charge Effects by Spectral Response, Steady State Charge Collection and Transient Photocurrents in Thick a-Si:H Pin-Diodes

1996 ◽  
Vol 420 ◽  
Author(s):  
J.-H. Zollondz ◽  
R. Brüggemann ◽  
S. Reynolds ◽  
C. Main ◽  
W. Gao ◽  
...  
Keyword(s):  
Steady State ◽  
Defect Density ◽  
Collection Efficiency ◽  
Spectral Response ◽  
Photon Flux ◽  
Charge Collection ◽  
Internal Variables ◽  
Pin Diodes ◽  
Charge Effects ◽  
Amplification Ratio

AbstractCharge collection, transient photocurrents and collection efficiency under additional bias illumination were used to characterize 3–4 micron thick a-Si:H pin-diodes. The wavelength dependent decrease or increase in the spectral response, depending on the bias flux and absorption depth, is related to the distribution of the electric field, recombination and majority carrier diffusion. At higher photon flux an overshoot in the transient photocurrent after switch-on of steady illumination indicates the time scale for the changes in internal variables. Collection efficiencies under large bias monochromatic photon flux well in excess of the maximum value of 100 % for probe beam generated carriers are observed with a large amplification ratio. These efficiencies sensitively depend both on the applied voltage and the defect density. Numerical modelling reveals the influence of internal variables on the transient and steady state photocurrents under the different illumination conditions.

Photocarrier Transport and Recombination in Amorphous Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
C.R. Wronski ◽  
R.M. Dawson ◽  
M. Gunes ◽  
Y.M. Li ◽  
R.W. Collins
Keyword(s):  
Solar Cell ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Room Temperature ◽  
Dark Conductivity ◽  
Conductivity Measurements ◽  
Dangling Bond ◽  
Dual Beam ◽  
Temperature Electron ◽  
Gap States

The effect of microstructure in undoped a-Si:H films on carrier transport, recombination, densities of midgap states and solar cell characteristics has been investigated. Extended state mobilities of electrons were obtained from photo and dark conductivity measurements between 40° C and 190° C and the gap states characterized using Dual Beam Photoconductivity. In these films the estimated room temperature electron mobilities increase from about 1 to 30 cm2/V sec as the dihydride concentrations and void volume fractions decrease. It is found that the carrier mobility-lifetime products are not solely determined by the dangling bond states. The effects of changes in the mobilities and midgap states on p-i-n homojunction solar cell characteristics are presented and discussed.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

scholarly journals Single-electron detection utilizing coupled nonlinear microresonators

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Xuefeng Wang ◽  
Xueyong Wei ◽  
Dong Pu ◽  
Ronghua Huan
Keyword(s):  
Scientific Community ◽  
Room Temperature ◽  
Detection Method ◽  
Single Electron ◽  
Nonlinear Coupling ◽  
Electron Charge ◽  
Micromechanical Resonators ◽  
Charge Detection ◽  
Simple Strategy ◽  
Electron Detection

Abstract Since the discovery of the electron, the accurate detection of electrical charges has been a dream of the scientific community. Owing to some remarkable advantages, micro/nanoelectromechanical system-based resonators have been used to design electrometers with excellent sensitivity and resolution. Here, we demonstrate a novel ultrasensitive charge detection method utilizing nonlinear coupling in two micromechanical resonators. We achieve single-electron charge detection with a high resolution up to 0.197 ± 0.056 $${\mathrm{e}}/\sqrt {{\mathrm{Hz}}}$$ e / Hz at room temperature. Our findings provide a simple strategy for measuring electron charges with extreme accuracy.

scholarly journals Radiation Tolerance in Nano-Structured Crystalline Fe(Cr)/Amorphous SiOC Composite

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 147
Author(s):  
Qing Su ◽  
Tianyao Wang ◽  
Lin Shao ◽  
Michael Nastasi
Keyword(s):  
Amorphous Silicon ◽  
Grain Growth ◽  
Irradiation Dose ◽  
Room Temperature ◽  
Silicon Oxycarbide ◽  
Radiation Response ◽  
Radiation Tolerance ◽  
Width Direction ◽  
Cr Film ◽  
Radiation Tolerant

The management of irradiation defects is one of key challenges for structural materials in current and future reactor systems. To develop radiation tolerant alloys for service in extreme irradiation environments, the Fe self-ion radiation response of nanocomposites composed of amorphous silicon oxycarbide (SiOC) and crystalline Fe(Cr) were examined at 10, 20, and 50 displacements per atom damage levels. Grain growth in width direction was observed to increase with increasing irradiation dose in both Fe(Cr) films and Fe(Cr) layers in the nanocomposite after irradiation at room temperature. However, compared to the Fe(Cr) film, the Fe(Cr) layers in the nanocomposite exhibited ~50% less grain growth at the same damage levels, suggesting that interfaces in the nanocomposite were defect sinks. Moreover, the addition of Cr to α-Fe was shown to suppress its grain growth under irradiation for both the composite and non-composite case, consistent with earlier molecular dynamic (MD) modeling studies.

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