Kinetics of Both Defects and Electron and Hole Diffusion Lengths During Light-Soaking in a-Si:H Films

1996 ◽  
Vol 420 ◽  
Author(s):  
A. S. Abramov ◽  
A. I. Kosarev ◽  
P. Roca i Cabarrocas ◽  
A. J. Vinogradov
Keyword(s):  
Diffusion Length ◽  
Initial Time ◽  
Characteristic Parameters ◽  
Stretched Exponential ◽  
Kinetics Of ◽  
Hole Diffusion Length

AbstractConcomitant studies of kinetics of defects ND(t), photoconductivity σph(t), electron and hole diffision lengths Le(t), Lh(t) during light soaking have been carried out. The data have been fitted by stretched exponential expressions and characteristic parameters of kinetics have been determined. Correlation between the kinetics is discussed. In contrast to Nd(t), σph(t) and Le(t), the hole diffusion length Lh(t) was observed to remain constant during initial time (˜ 103s) and then decreased with characteri stic time ˜ 104s.

scholarly journals Contrasting Electron and Hole Transfer Dynamics from CH(NH2)2PbI3 Perovskite Quantum Dots to Charge Transport Layers

2020 ◽  
Vol 10 (16) ◽  
pp. 5553
Author(s):  
Zhigang Lou ◽  
Shuyan Liang ◽  
Jiabei Yuan ◽  
Kang Ji ◽  
Jianyu Yuan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Charge Transport ◽  
Transient Absorption ◽  
Diffusion Length ◽  
Temporal Evolution ◽  
Fine Tuning ◽  
Transient Absorption Spectroscopy ◽  
Hole Transfer ◽  
Perovskite Quantum Dots ◽  
Hole Diffusion Length

In this work, the ultrafast transient absorption spectroscopy (TAs) was utilized to first investigate the charge transfer from the emerging FAPbI3 (FA = CH(NH2)2) perovskite quantum dots (PQDs) to charge transport layers. Specifically, we compared the TAs in pure FAPbI3 PQDs, PQDs grown with both electron and hole transfer layers (ETL and HTL), and PQDs with only ETL or HTL. The TA signals induced by photoexcited electrons decay much faster in PQDs samples with the ETL (~20 ps) compared to the pure FAPbI3 PQDs (>1 ns). These results reveal that electrons can effectively transport between coupled PQDs and transfer to the ETL (TiO2) at a time scale of 20 ps, much faster than the bimolecular charge recombination inside the PQDs (>1 ns), and the electron transfer efficiency is estimated to be close to 100%. In contrast, the temporal evolution of the TA signals in the PQDs with and without HTL exhibit negligible change, and no substantive hole transfer to the HTL (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], PTAA) occurs within 1 ns. The much slower hole transfer implies the further potential of increasing the overall photo-carrier conversion efficiency through enhancing the hole diffusion length and fine-tuning the coupling between the HTL and PQDs.

Recombination Processes in 4H-SiC pn Structures

2016 ◽  
Vol 858 ◽  
pp. 345-348 ◽  
Author(s):  
Anatoly M. Strel'chuk ◽  
Baptiste Berenguier ◽  
Eugene B. Yakimov ◽  
Laurent Ottaviani
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Diffusion Length ◽  
Induced Current ◽  
Donor Concentration ◽  
Reverse Voltage ◽  
Recombination Processes ◽  
Electron Beam Induced Current ◽  
Switching Characteristics ◽  
Hole Diffusion Length

Commercial 4H-SiC p+n structures with an uncompensated donor concentration (Nd-Na) of ~1.5∙1015 cm-3 in the n-type epitaxial layer are studied. The measurement of the photocurrent, electron beam induced current and transient switching characteristics (from forward to reverse voltage), altogether showed that the value of the hole diffusion length, about 2 μm at room temperature, increases to at least 7 μm at 620 K.

Hole diffusion length in high purity n-GaAs

1972 ◽  
Vol 15 (8) ◽  
pp. 865-868 ◽  
Author(s):  
R.D. Ryan ◽  
J.E. Eberhardt
Keyword(s):  
High Purity ◽  
Diffusion Length ◽  
Hole Diffusion Length

scholarly journals Kinetics of atrazine degradation by photocatalytic process in aqueous solution

2003 ◽  
Vol 5 (2) ◽  
pp. 87-93 ◽  
Author(s):  
O. Zahraa ◽  
L. Sauvanaud ◽  
G. Hamard ◽  
M. Bouchy
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Salicylic Acid ◽  
Photocatalytic Degradation ◽  
Competitive Adsorption ◽  
Initial Time ◽  
Photocatalytic Process ◽  
Herbicide Atrazine ◽  
Kinetics Of ◽  
Atrazine Degradation

The photocatalytic degradation of the herbicide atrazine has been studied using suspended titanium dioxide as catalyst. The Langmuir-Hinshelwood model is satisfactorily obeyed at initial time and in the course of the reaction. The rate of degradation is found to be enhanced by the addition of persulphate ions. Competitive degradation between atrazine and other pollutants is satisfactorily interpreted as monitored by a competitive adsorption of the reactants. As a consequence, efficient reactants such as salicylic acid and phenol delay atrazine degradation until these compounds are degraded.

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