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.

Photoinduced Space Charge Effects in a-Si:H Solar Cells

1999 ◽  
Vol 557 ◽  
Author(s):  
T. Unold ◽  
T. Binnewies ◽  
R. Brüggemann ◽  
G.H. Bauer
Keyword(s):  
Numerical Simulation ◽  
Solar Cells ◽  
Space Charge ◽  
Probe Beam ◽  
Defect Density ◽  
Photon Flux ◽  
Charge Collection ◽  
Small Signal ◽  
Charge Effects ◽  
Signal Probe

AbstractWe have investigated charge collection in thin amorphous silicon solar cells under light bias illumination, both experimentally and by numerical simulation. In such charge collection experiments, space charge due to trapped bias-light generated carriers leads to an enhancement of a small signal probe beam charge collection. It is found that this enhancement of the small signal charge collection is strongly dependent on the diode thickness and the defect density in the samples. In particular for thin diodes (d < 0.5 microns) the charge collection enhancement can be shown to increase with light-induced degradation of the devices. The effect of these material parameters as well as other experimental parameters, such as light bias and probe beam photon flux, will be demonstrated by means of numerical simulation.

Conditions for Collection Efficiencies Greater than one Hundred Percent

1997 ◽  
Vol 467 ◽  
Author(s):  
R. Brüggemann ◽  
J. H. Zollondz ◽  
C. Main ◽  
W. Gao
Keyword(s):  
Numerical Modelling ◽  
Absorption Coefficient ◽  
Collection Efficiency ◽  
Photon Flux ◽  
Large Collection ◽  
Probe Light ◽  
Pin Diodes ◽  
Sensor Applications ◽  
Probe Absorption ◽  
Side Bias

ABSTRACTAn account is given for the conditions under which the collection efficiency in hydrogen ated amorphous silicon pin-diodes increases to values larger than 100 %. By specific bias illumination through the p-side bias generated photocarriers are collected under certain probe beam conditions of the collection efficiency measurement, leading to apparent large collection efficiencies. By numerical modelling we investigated the influence of the diode thickness, bias photon flux and probe absorption coefficient as well as applied voltage for possible sensor applications which may utilise this optical amplifying principle. The alternative with bias light through the n-side and probe light through the p-side is also explored. Collection efficiency values determined by the photogating of bias generated holes become only slightly larger than 100 % in contrast to the electron case where values in excess of 3000 % are presented.

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.

scholarly journals Magnetoactive elastomers for magnetically tunable vibrating sensor systems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tatiana I. Becker ◽  
Yuriy L. Raikher ◽  
Oleg V. Stolbov ◽  
Valter Böhm ◽  
Klaus Zimmermann
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Smart Materials ◽  
Excitation Frequency ◽  
Experimental Studies ◽  
Uniform Field ◽  
Sensor Systems ◽  
Ongoing Research ◽  
Amplification Ratio ◽  
Field Distortion

Abstract Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled “configuration” can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes.

3D imaging of radiation damage in silicon sensor and spatial mapping of charge collection efficiency

2013 ◽  
Vol 8 (03) ◽  
pp. C03023-C03023 ◽  
Author(s):  
M Jakubek ◽  
J Jakubek ◽  
J Zemlicka ◽  
M Platkevic ◽  
V Havranek ◽  
...  
Keyword(s):  
Radiation Damage ◽  
3D Imaging ◽  
Collection Efficiency ◽  
Charge Collection ◽  
Spatial Mapping ◽  
Charge Collection Efficiency ◽  
Silicon Sensor

Spectral response of steady-state photoluminescence from GaAs1-xPx layers grown on a SiGe/Si system

2017 ◽  
Vol 111 (12) ◽  
pp. 121103 ◽  
Author(s):  
Li Wang ◽  
Michael E. Pollard ◽  
Mattias Klaus Juhl ◽  
Brianna Conrad ◽  
Anastasia Soeriyadi ◽  
...  
Keyword(s):  
Steady State ◽  
Spectral Response
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