Relaxation Measurements of the Persistent Photoconductivity in Sulfur-Doped a-Si:H.

1996 ◽  
Vol 420 ◽  
Author(s):  
D. Quicker ◽  
J. Kakalios
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Sulfur Atom ◽  
Hydrogenated Amorphous Silicon ◽  
Persistent Photoconductivity ◽  
Sulfur Concentration ◽  
Illumination Time ◽  
Thermally Activated ◽  
Relaxation Measurements ◽  
Hydrogenated Amorphous

AbstractThe slow relaxation of the persistent photoconductivity (PPC) effect in sulfur-doped hydrogenated amorphous silicon (a-Si:H) has been measured as a function of temperature and illumination time. The relaxation is found to be thermally activated, with an activation energy which varies with sulfur concentration, while illuminating the film for a longer time leads to a longer relaxation time. A correlation is observed between changes of the photoconductivity during illumination and the magnitude of the PPC effect following illumination. These effects are also observed in compensated a-Si:H, suggesting that the mechanism for the PPC effect is the same in both sulfur-doped a-Si:H and compensated a-Si:H. The presence of donor and compensating acceptor states in sulfur-doped a-Si:H could arise from valence alternation pair sulfur atom defects.

Annealing of Metastable Recombination Centers in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
Jong-Hwan Yoon ◽  
Yoon-Zik Lee
Keyword(s):  
Relaxation Time ◽  
Amorphous Silicon ◽  
Light Exposure ◽  
Hydrogenated Amorphous Silicon ◽  
Activation Energies ◽  
Exponential Time ◽  
Thermally Activated ◽  
Recombination Centers ◽  
Hydrogenated Amorphous ◽  
Annealing Defects

ABSTRACTWe report results on the annealing behaviors of light- and deposition-induced metastable recombination centers, as measured by steady-state photoconductivity, in undoped hydrogenated amorphous silicon. The relaxation time inferred from the stretched-exponential time law reveals a thermally activated behavior, and the activation energies are nearly identical in both (Ea=1.1eV). This value is much less than that of the light-induced darkconductivity relaxation (Ea=1.7eV) measured simultaneously with photoconductivity. While in the deposition-induced case both activation energies of dark- and photoconductivity relaxation time are identical. These results support that there is more than one kind of defect created by light exposure, and at least, as considering activation energies for annealing defects, the light-induced recombination center differ from other metastable defects.

Persistent photoconductivity in hydrogenated amorphous silicon

1986 ◽  
Vol 59 (3) ◽  
pp. 177-181 ◽  
Author(s):  
Suk-Ho Choi ◽  
Gyeong-Lyong Park ◽  
Choochon Lee ◽  
Jin Jang
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Persistent Photoconductivity ◽  
Hydrogenated Amorphous

Change of Spin-Lattice Relaxation Time with Light Soaking for Defects in Hydrogenated Amorphous Silicon

1998 ◽  
Vol 37 (Part 1, No. 10) ◽  
pp. 5470-5473
Author(s):  
Wei-Chi Lai ◽  
Chun-Yen Chang ◽  
Meiso Yokoyama ◽  
Jen-Dar Guo ◽  
Jian-Shihn Tsang ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Hydrogenated Amorphous

Influence Of The Density of States and Series Resistance on the Field-Effect Activation Energy in a-Si:H TFT

1996 ◽  
Vol 424 ◽  
Author(s):  
Chun-Ying Chen ◽  
Jerzy Kanicki
Keyword(s):  
Activation Energy ◽  
Density Of States ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Series Resistance ◽  
Hydrogenated Amorphous Silicon ◽  
Two Dimensional ◽  
Source Current ◽  
Dimensional Simulation ◽  
Hydrogenated Amorphous

AbstractWe have proposed a new two-dimensional simulation model, which takes into account the density of states of hydrogenated amorphous silicon (a-Si:H) and temperature-dependence of the source/drain series resistances (Rs), to explain the dependence of the activation energy (Eact) of drain-source current (IDs) on gate-source bias (VGs) in a-Si:H thin-film transistors (TFTs). We found that the influence of series resistance cannot be ignored, else an overestimated Eact will result. The results of our simulation are in agreement with experimentally observed saturation of the Eact at higher VGs.

scholarly journals The Electronic Transport Mechanism in Amorphous Tetrahedrally-Coordinated Carbon Films

1997 ◽  
Vol 498 ◽  
Author(s):  
J. P. Sullivan ◽  
T. A. Friedmann ◽  
R. G. Dunn ◽  
E. B. Stechel ◽  
P. A. Schultz ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Stress Relaxation ◽  
Electronic Transport ◽  
Transport Mechanism ◽  
Thermal Evolution ◽  
Carbon Films ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Relaxation Measurements

ABSTRACTThe electronic transport mechanism in tetrahedrally-coordinated amorphous carbon was investigated using measurements of stress relaxation, thermal evolution of electrical conductivity, and temperature-dependent conductivity measurements. Stress relaxation measurements were used to determine the change in 3-fold coordinated carbon concentration, and the electrical conductivity was correlated to this change. It was found that the conductivity was exponentially proportional to the change in 3-fold concentration, indicating a tunneling or hopping transport mechanism. It was also found that the activation energy for transport decreased with increasing anneal temperature. The decrease in activation energy was responsible for the observed increase in electrical conductivity. A model is described wherein the transport in this material is described by thermally activated conduction along 3-fold linkages or chains with variable range and variable orientation hopping. Thermal annealing leads to chain ripening and a reduction in the activation energy for transport.

Charge Trapping by Deep Donors in Si-Doped AlxGa1-xAS

1985 ◽  
Vol 46 ◽  
Author(s):  
P. M. Mooney ◽  
N. S. Caswell ◽  
P. M. Solomon ◽  
S. L. Wright
Keyword(s):  
Activation Energy ◽  
Energy Range ◽  
Charge Trapping ◽  
Lattice Relaxation ◽  
Persistent Photoconductivity ◽  
Relaxation Model ◽  
Thermally Activated ◽  
Large Lattice ◽  
Si Doped ◽  
Kinetics Of

AbstractThe kinetics of charge capture by deep donors in AlxGa1-xAs have been measured. The time dependence indicates that a single energy cannot be used to describe the trap. A model assuming thermally activated capture into a resonance in the conduction band with a range of energies gives excellent fits to the data and provides a measure of the energy range for the trap. This model is consistent with the large lattice relaxation model for DX centers. The increase of the activation energy for capture as the Al mole fraction is decreased contradicts the model which attributes the decay of the persistent photoconductivity to tunneling through the heterojunction barrier in modulationdoped structures.

Light-Induced Metastable Changes in a-SiSx:H

1995 ◽  
Vol 377 ◽  
Author(s):  
S. L. Wang ◽  
P. C. Taylor
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Annealing Temperature ◽  
Dark Conductivity ◽  
Sulfur Concentration ◽  
Thermally Activated ◽  
Dramatic Difference ◽  
The Creation ◽  
Sulfur Donor

ABSTRACTMetastable light-induced increases in the dark conductivities of a-SiSx:H alloys are explained as photo-activation of hydrogen-passivated sulfur donor sites. For a sulfur concentration (sulfur-to-silicon ratio) of 5.6 × 103 the excess dark conductivity as a function of illumination temperature is thermally activated with an activation energy of 0.72 eV. When the sulfur concentration is 3.3 × 102, the temperature dependence is very weak. This dramatic difference in the temperature dependence of the creation of increased dark conductivity is explained by a lowering of the annealing temperature for the metastable changes as the sulfur concentration increases. We discuss the influence of this new metastability on the possibility of obtaining more stable films.

Low Temperature Kinetics for the Growth and Decay of Band-Tallcarriers and Dangling Bonds in Hydrogenated Amorphous Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
Niko Schultz ◽  
P.C. Taylor
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Underlying Mechanism ◽  
Total Production ◽  
Dangling Bonds ◽  
Band Tail ◽  
Thermally Activated ◽  
Spin Resonance ◽  
Hydrogenated Amorphous ◽  
Kinetics Of

AbstractIn hydrogenated amorphous silicon (a-Si:H), the kinetics of the light induced production of silicon dangling bonds and long-lived band-tail electrons and holes has been measured at temperatures between 65 and 340 K using light induced electron spin resonance (LESR). Below about 150 K the measurement of Si dangling bonds is masked by the accumulation of long-lived band-tail carriers. The kinetics of the growth and decay of these long-lived, trapped band-tail carriers consists of very fast components (τ < ms) and very long components (τ > h). Optical quenching of these long-lived carriers is not efficient at quenching energies of 0.6 eV. Afler removal of these long-lived band tail carriers by annealing at about 250 K we find that the total production of silicon dangling bonds at 65 K after 10 h of illumination is about a factor of five less than at 340 K. The dangling bond production resulting from 10 h of illumination is well fit to an underlying mechanism that, if thermally activated, exhibits an activation energy of approximately 10 meV.

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