Transport Properties of Compensated μc-Si:H

1996 ◽  
Vol 420 ◽  
Author(s):  
N. Wyrsch ◽  
M. Goerlitzer ◽  
N. Beck ◽  
J. Meier ◽  
A. Shah
Keyword(s):  
Transport Properties ◽  
Room Temperature ◽  
Time Of Flight ◽  
Drift Mobility ◽  
Hole Transport ◽  
Microcrystalline Silicon ◽  
Dispersive Transport ◽  
Experimental Values ◽  
First Time ◽  
Photovoltaic Material

AbstractElectron and hole transport in completely microcrystalline silicon (μc-Si) p-i-n cells and in intrinsic or near intrinsic μc-Si layers have been investigated, for the first time, by time of flight (TOF) at temperatures between 100 and 400 K.At room temperature, both electron and hole drift mobilities were found to be between 0.2 and 1 cm2 V-ls-1. No trace of anomalous dispersive transport was observed, neither for electrons nor for holes, down to 100 K. A decrease of the drift mobility was observed when the temperature was raised from room temperature to 400 K as usually observed in crystalline semiconductors. However, these experimental values of the drift mobilities appear more puzzling than helpful for the comprehension of this “new” photovoltaic material.

Time-of-Flight Measurements in a-Si:H Between Room Temperature and 130° C°

1987 ◽  
Vol 95 ◽  
Author(s):  
D. S. Shen ◽  
S. Aljishi ◽  
Z E. Smith ◽  
J. P. Conde ◽  
V. Chu ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Room Temperature ◽  
Time Of Flight ◽  
High Sensitivity ◽  
Drift Mobility ◽  
Hole Transport ◽  
Dispersive Transport ◽  
Band Tail ◽  
Flight Measurements

AbstractThe drift mobility μd and the mobility-lifetime product μτ in undoped a-Si:H have been studied up to 130°C. The electron μde is temperature-activated with Eae = 0.13 to 0.16 eV. The electron (μτ)e increases with temperature T. For hole transport, we observe the transition from dispersive to non-dispersive transport with increasing T. The hole μdh is ∼ 1/100 of μde, and is activated with Eah = 0.34 to 0.48eV. The hole (μτ)h does not change much with T. A computer simulation demonstrates the high sensitivity of μd to the band tail width.

scholarly journals Optical and Electrical Properties of Undoped Microcrystalline Silicon Deposited by the VHF-GD with Different Dilutions of Silane in Hydrogen

1996 ◽  
Vol 452 ◽  
Author(s):  
N. Beck ◽  
P. Orres ◽  
J. Fric ◽  
Z. Remeš ◽  
A. Poruba ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Time Of Flight ◽  
Optical And Electrical Properties ◽  
Microcrystalline Silicon ◽  
Transient Time ◽  
Deep Traps ◽  
Flight Measurements ◽  
Strong Dilution

AbstractWe show that the optical and electrical properties of microcrystalline silicon (μc-Si:H) deposited by the VHF-GD technique at 110 MHz can considerably be tuned by changing the dilution ratio of silane to hydrogen.With increasing silane dilution we observe enhanced optical absorption for energies below 2 eV due to the transition of the material from amorphous / microcrystalline mixture to a pure microcrystalline phase. Simultaneously, the light scattering and the defect absorption increases. Strong dilution also promotes the incorporation of impurities into the material, leading to a pronounced extrinsic behaviour as seen from the decrease of the activiation energy of the electrical conductivity.The electrical properties were investigated in the dark by the Time of Flight technique. We measured drift mobilities at room temperature which slightly increase with dilution, reaching values of 3 cm2/Vs for electrons and 1.2 cm2/Vs for holes. The ratio between electron and hole drift mobilities is found to be around 2 for all samples studied, similar to that of crystalline silicon.Furthermore, post-transient Time of Flight measurements revealed detrimental electron deep traps in low dilution material.

Electronic transport and structure of microcrystalline silicon deposited by the VHF-GD technique

1997 ◽  
Vol 467 ◽  
Author(s):  
M. Goerlitzer ◽  
N. Beck ◽  
P. Torres ◽  
U. Kroll ◽  
H. Keppner ◽  
...  
Keyword(s):  
Transport Properties ◽  
Electronic Transport ◽  
Growth Direction ◽  
Dark Conductivity ◽  
Drift Mobility ◽  
X Ray Diffraction ◽  
Microcrystalline Silicon ◽  
Direction Parallel ◽  
X Ray ◽  
Diffraction Patterns

ABSTRACTElectronic transport parallel and perpendicular to growth direction has been studied in a series of microcrystalline silicon samples obtained by various dilutions of silane in hydrogen. It is clearly shown that the transport properties (dark conductivity, drift mobility, ambipolar diffusion length and photoconductivity) under dark and under illumination conditions are enhanced as the dilution is increased. Furthermore, these films exhibit no degradation upon light-soaking. X-Ray diffraction patterns of the samples confirm that there is a correlation between the amount of crystalline fraction in the samples and the transport properties, as well as a preferential orientation along the growth direction. A similar correlation is found with the shift of the Si-H stretching mode peak of the infrared spectra (IR). Because transport properties have been measured by different techniques (dark conductivity, ambipolar length and photoconductivity in the direction perpendicular to growth direction, drift mobility in the direction parallel to growth direction), no statement can be made about a possible anisotropy in transport, as it would be expected from the columnar shape of the crystallites.

scholarly journals Light absorption and hole-transport properties of copper corroles: from aggregates to a liquid crystal mesophase

2015 ◽  
Vol 39 (9) ◽  
pp. 7140-7146 ◽  
Author(s):  
Di Gao ◽  
Judicaelle Andeme Edzang ◽  
Abdou Karim Diallo ◽  
Thibault Dutronc ◽  
Teodor Silviu Balaban ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Transport Properties ◽  
Light Absorption ◽  
Room Temperature ◽  
Hole Transport ◽  
Crystal Phase ◽  
Liquid Crystal Phase

A room temperature corrole-based liquid crystal phase is described, fully characterized and compared to assemblies produced by simpler corrole derivatives.

A Novel Preparation Technique Termed “Chemical Annealing” to make a Rigid and Stable Si-Network

1991 ◽  
Vol 219 ◽  
Author(s):  
Hajime Shirai ◽  
Jun-Ichi Hanna ◽  
Isamu Shimizu
Keyword(s):  
Atomic Hydrogen ◽  
Room Temperature ◽  
Drift Mobility ◽  
Preparation Technique ◽  
Dispersive Transport ◽  
Optical Gap ◽  
Chemical Annealing ◽  
Flight Measurement ◽  
The Stability

ABSTRACTA novel preparation technique termed “Chemical Annealing (CA)” was developed with aim of making a stable and rigid structure of Si-network. The a-Si:H films were made by the alternate deposition of several tens angstrom thick a-Si:H and the treatment with atomic hydrogen or excited novel gases such as Ar* and He*. Hydrogen contents (CH) and optical gap (Eg) in the film prepared by this tecnique were able to reduced by CH of 1.5at%, and Eg of 1.5eV, respectively at substrate temperature:300C. All of them exhibited high photoconductivities in the level of 10-5 10-4 S/cm under illumination of 100mW/cm2. In the films with CH of 3at% or less, in particular, marked improvement was confirmed in the stability after light soaking. In addition, the time-of-flight measurement revealed a non-dispersive transport and a significant enhancement in the drift mobility of holes up to 0.2cmm2/Vs at room temperature in the film with CH : 5at% and Eg:1.65eV prepared at 300C. Advantages of the CA process are summarized together with the discussion of role of atomic hydrogen, excited novel gases such as Ar* and He* in the growing surface.

scholarly journals Hole Drift-Mobility Measurements and Multiple-Trapping in Microcrystalline Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
T. Dylla ◽  
F. Finger ◽  
E. A. Schiff
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Volume Fraction ◽  
Drift Mobility ◽  
Microcrystalline Silicon ◽  
Temperature Dependent ◽  
Multiple Trapping ◽  
Hole Band ◽  
Silicon Based ◽  
Flight Measurements

ABSTRACTWe present photocarrier time-of-flight measurements of the hole drift-mobility in microcrystalline silicon samples with a high crystalline volume fraction; typical room-temperature values are about 1 cm2/Vs. Temperature-dependent measurements are consistent with the model of multiple-trapping in an exponential bandtail. While this model has often been applied to amorphous silicon, its success for predominantly crystalline samples is unexpected. The valence bandtail width is 31 meV, which is about 10-20 meV smaller than values reported a-Si:H, and presumably reflects the greater order in the microcrystalline material. The hole band-mobility is about 1 cm2/Vs – essentially the same magnitude as has been reported for electrons and for holes in amorphous silicon, and suggesting that this magnitude is a basic characteristic of mobility-edges, at least in silicon-based materials. The attempt-frequency is about 109 s-1; this value is substantially smaller than the values 1011 - 1012 s-1 typically reported holes in amorphous silicon, but the physical significance of the parameter remains obscure.

Room-temperature white and color-tunable afterglow by manipulating multi-mode triplet emissions

2021 ◽  
Vol 9 (9) ◽  
pp. 3257-3263
Author(s):  
Jianwei Liu ◽  
Zhimin Ma ◽  
Zewei Li ◽  
Yan Liu ◽  
Xiaohua Fu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Component ◽  
Color Tunable ◽  
First Time ◽  
Multi Mode

Two isomers pDCzPyCN and oDCzPyCN are designed and synthesized. Amazingly, oDCzPyCN manifest white afterglow at room temperature. This is the first time that single-component white afterglow has finally been realized.

Dioxygen splitting at room temperature over distant binuclear transition metal centers in zeolites for direct oxidation of methane to methanol

2021 ◽  
Author(s):  
Kinga Mlekodaj ◽  
Mariia Lemishka ◽  
Stepan Sklenak ◽  
Jiri Dedecek ◽  
Edyta Tabor
Keyword(s):  
Transition Metal ◽  
Room Temperature ◽  
Direct Oxidation ◽  
Metal Centers ◽  
Oxidation Of Methane ◽  
First Time

Here we demonstrate for the first time the splitting of dioxygen at RT over distant binuclear transition metal (M = Ni, Mn, and Co) centers stabilized in ferrierite zeolite. Cleaved...

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