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.

Mechanical Spectroscopy Study on the Light Soaking Effect on Hydrogenated Amorphous Silicon

2012 ◽  
Vol 184 ◽  
pp. 416-421 ◽  
Author(s):  
H. Mizubayashi ◽  
I. Sakata ◽  
H. Tanimoto
Keyword(s):  
Internal Friction ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Wide Distribution ◽  
Activation Energies ◽  
Mechanical Spectroscopy ◽  
Induced Changes ◽  
Mild Temperature ◽  
Hydrogenated Amorphous

For hydrogenated amorphous silicon (a-Si:H) films deposited at temperatures between 423 K and 623 K (a-Si:H423Kand so on), the light-induced changes in the internal friction between 80 K and 400 K were studied. The internal friction is associated with H2motion in microvoid networks, and shows the mild temperature dependence between about 80 K and 300 K (Q-180-300K) and the almost linear increase above 300 K (Q-1>300K). BothQ-180-300KandQ-1>300Kdecrease with increasing the deposition temperature, and show the mild temperature dependence ina-Si:H623K. The white light soaking with 100 mW/cm2(WLS100and so on) below 300 K caused a change inQ-180-300Kand no changes inQ-1>300K, respectively, and the light-induced changes inQ-180-300Krecovered after annealing at 423 K. The wide distribution of activation energies for H2motions between microvoids indicate that most of neighboring microvoids are connected through windows, i.e., the microvoid networks are existing ina-Si:H, and the spatially loose or solid structures are responsible for the low or high activation energies for the H2motion between microvoids, respectively. Furthermore, the light-induced hydrogen evolution (LIHE) was observed for WLS200to WLS400in a vacuum between 400 and 500 K, resulting in the disappearance of the internal friction due to the H2motion in the microvoid network.

Effect of ultraviolet light exposure to boron doped hydrogenated amorphous silicon oxide thin film

2012 ◽  
Vol 260 ◽  
pp. 17-22 ◽  
Author(s):  
Seungsin Baek ◽  
S.M. Iftiquar ◽  
Juyeon Jang ◽  
Sunhwa Lee ◽  
Minbum Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Ultraviolet Light ◽  
Silicon Oxide ◽  
Light Exposure ◽  
Hydrogenated Amorphous Silicon ◽  
Oxide Thin Film ◽  
Boron Doped ◽  
Amorphous Silicon Oxide ◽  
Hydrogenated Amorphous

Stability of p-i-n hydrogenated amorphous silicon solar cells to light exposure

Solar Cells ◽  
1983 ◽  
Vol 9 (1-2) ◽  
pp. 3-12 ◽  
Author(s):  
Y. Uchida ◽  
M. Nishiura ◽  
H. Sakai ◽  
H. Haruki
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Light Exposure ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Solar Cells ◽  
Hydrogenated Amorphous

Impurities and Metastable Centers in Amorphous Silicon Solar Cells

1986 ◽  
Vol 70 ◽  
Author(s):  
D. E. Carlson
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Solar Cells ◽  
Internal Surfaces ◽  
Induced Motion ◽  
Recombination Centers ◽  
The Creation ◽  
Electronic Activity ◽  
Hydrogenated Amorphous

ABSTRACTAmorphous silicon solar cells are adversely affected by impurities through the creation of traps, recombination centers and metastable centers. The microstructure of discharged-produced, hydrogenated amorphous silicon (a-Si:H) appears to be strongly affected by the presence of impurities in the discharge atmosphere. A model is developed in which impurities create microvoids in a-Si:H, and traps, recombination centers and metastable centers are associated with the internal surfaces of the microvoids. In this model, hydrogen plays an important role in determining the electronic activity and diffusivity of impurities, and metastable centers are created by the trapping of holes near microvoids and the induced motion of hydrogen on the internal surfaces of the microvoids.

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.

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

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.

Changes of Drift Mobility in a-Si:H with Light Exposure and Doping

1987 ◽  
Vol 95 ◽  
Author(s):  
J. Takada ◽  
H. Fritzsche
Keyword(s):  
Light Intensity ◽  
Amorphous Silicon ◽  
Light Exposure ◽  
Hydrogenated Amorphous Silicon ◽  
Drift Mobility ◽  
Mobility Edge ◽  
Strong Light ◽  
Quasi Fermi Level ◽  
Multiple Trapping ◽  
Hydrogenated Amorphous

AbstractMeasurements of the drift mobility μ of photo-excited electrons in n-type hydrogenated amorphous silicon (a-Si:H) as a function of light intensity are reported. The value of μ increases as the quasi Fermi level is moved closer to the transport states in accordance with the multiple trapping theory. The drift mobility decreases with increasing doping as well as with an increase in the concentration of metastable dangling bonds defects by strong light exposures. This decrease in μ between 300 and 360K can be explained by a corresponding decrease in the microscopic mobility, by an increase in the density of tail states within 0.35eV below the electron mobility edge, or by a combination of both these effects.

Experimental Determination of the Dark Fermi Level in Hydrogenated Amorphous Silicon.

1992 ◽  
Vol 258 ◽  
Author(s):  
R.M. Dawson ◽  
S. Nag ◽  
M. Gunes ◽  
C.R. Wronski ◽  
M. Bennett ◽  
...  
Keyword(s):  
Fermi Level ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Activation Energies ◽  
Key Factors ◽  
In Series ◽  
Measured Activation ◽  
Hydrogenated Amorphous ◽  
Probe Measurements

ABSTRACTThe position of the dark fermi level in hydrogenated amorphous silicon (a-Si:H) is important in determining its electrical properties and is a key parameter in the detailed modelling of materials and devices. The activation energies of conductivities have been investigated on intrinsic a-Si:H films from various laboratories where the slopes of the Arrhenius plots have ranged from 0.27 eV to 0.87 eV. In many cases, marked differences are found between the results obtained from two and four probe measurements, highlighting the importance of the four probe configuration. Results are presented which help to explain the scatter in the measured activation energies between intrinsic films of a-Si:H. Differences in the activation energies are discussed in terms of current limiting processes which act in series with the material bulk resistance. It will be shown that the conductivity of the film and the contact are key factors in assessing whether the position of the fermi level can be accurately determined from a two contact measurement.

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