EBIC diffusion length of dislocated silicon

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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Determining the exciton diffusion length of copper phthalocyanine in operating planar-heterojunction organic solar cells

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020190322 ◽

2020 ◽

Vol 89 (3) ◽

pp. 30201 ◽

Cited By ~ 1

Author(s):

Xi Guan ◽

Shiyu Wang ◽

Wenxing Liu ◽

Dashan Qin ◽

Dayan Ban

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

Diffusion Length ◽

Copper Phthalocyanine ◽

Short Circuit ◽

Thick Layer ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Exciton Diffusion ◽

Exciton Diffusion Length

Organic solar cells based on planar copper phthalocyanine (CuPc)/C60 heterojunction have been characterized, in which a 2 nm-thick layer of bathocuproine (BCP) is inserted into the CuPc layer. The thin layer of BCP allows hole current to tunnel it through but blocks the exciton diffusion, thereby altering the steady-state exciton profile in the CuPc zone (zone 1) sandwiched between BCP and C60. The short-circuit current density (JSC) of device is limited by the hole-exciton scattering effect at the BCP/CuPc (zone 1) interface. Based on the variation of JSC with the width of zone 1, the exciton diffusion length of CuPc is deduced to be 12.5–15 nm. The current research provides an easy and helpful method to determine the exciton diffusion lengths of organic electron donors.

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Grain boundary effect on spectral response and effective diffusion length in polycrystalline silicon solar cells

International Journal of Electronics ◽

10.1080/00207218508939094 ◽

1985 ◽

Vol 58 (6) ◽

pp. 981-996 ◽

Cited By ~ 1

Author(s):

A. AGARWAL ◽

D. BANA ◽

B. PRASAD ◽

C. M. SINGAL

Keyword(s):

Solar Cells ◽

Grain Boundary ◽

Polycrystalline Silicon ◽

Diffusion Length ◽

Boundary Effect ◽

Spectral Response ◽

Effective Diffusion ◽

Silicon Solar Cells ◽

Grain Boundary Effect

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Carbon-coated TiNb2O7 nanosheet arrays as self-supported high mass-loading anode for flexible Li-ion battery

Chemical Communications ◽

10.1039/d0cc08251a ◽

2021 ◽

Author(s):

Jinquan Zhou ◽

Haoyang Dong ◽

Yao Chen ◽

yihua Ye ◽

Liang Xiao ◽

...

Keyword(s):

Diffusion Length ◽

High Mass ◽

Carbon Cloth ◽

Mass Loading ◽

Solvothermal Process ◽

Li Ion Battery ◽

Nanosheet Arrays ◽

Carbon Coated ◽

Li Ion ◽

First Time

TiNb2O7 anode constructed with carbon-coated nanosheet arrays on carbon cloth is prepared by a facile solvothermal process and post carbon-coating for the first time. With nanosized diffusion-length and reduced polarization...

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Diamine vapor treatment of viscoelastic graphene oxide liquid crystal for gas barrier coating

Scientific Reports ◽

10.1038/s41598-021-88955-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Seung Eun Choi ◽

Sung-Soo Kim ◽

Eunji Choi ◽

Ji Hoon Kim ◽

Yunkyu Choi ◽

...

Keyword(s):

Graphene Oxide ◽

Liquid Crystal ◽

Diffusion Length ◽

Barrier Properties ◽

Gas Barrier ◽

Barrier Coating ◽

Coating Method ◽

Gas Molecules ◽

Pet Film ◽

Vapor Treatment

AbstractA layered graphene oxide/ethylenediamine (GO/EDA) composite film was developed by exposing aqueous GO liquid crystal (GOLC) coating to EDA vapor and its effects on the gas barrier performance of GO film were systematically investigated. When a GO/EDA coating with a thickness of approximately 1 μm was applied to a neat polyethylene terephthalate (PET) film, the resultant film was highly impermeable to gas molecules, particularly reducing the gas permeance up to 99.6% for He and 98.5% for H2 in comparison to the neat PET film. The gas barrier properties can be attributed to the long diffusion length through stacked GO nanosheets. The EDA can crosslink oxygen-containing groups of GO, enhancing the mechanical properties of the GO/EDA coating with hardness and elastic modulus values up to 1.14 and 28.7 GPa, respectively. By the synergistic effect of the viscoelastic properties of GOLC and the volatility of EDA, this coating method can be applied to complex geometries and EDA intercalation can be spontaneously achieved through the scaffold of the GOLC.

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Continuous-Flow Photocatalytic Microfluidic-Reactor for the Treatment of Aqueous Contaminants, Simplicity, and Complexity: A Mini-Review

Symmetry ◽

10.3390/sym13081325 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1325

Author(s):

Zhongwei Gao ◽

Changqing Pan ◽

Chang-Ho Choi ◽

Chih-Hung Chang

Keyword(s):

Continuous Flow ◽

Lower Energy ◽

High Efficiency ◽

Diffusion Length ◽

Physical Adsorption ◽

Chemical Oxidation ◽

Microfluidic Reactor ◽

Global Issue ◽

The Individual ◽

Aqueous Contaminants

Water pollution is a growing global issue; there are many approaches to treating wastewater, including chemical coagulation, physical adsorption, and chemical oxidation. The photocatalysis process has provided a solution for removing pollutants from wastewater, where the pair of the photoelectron and hole works through an asymmetric way to degrade the contaminants under UV irradiation. This method offers an alternative route for treating the pollutant with a lower energy cost, high efficiency, and fewer byproducts. A continuous-flow microfluidic reactor has a channel size from tens to thousands of micrometers, providing uniform irradiation and short diffusion length. It can enhance the conversion efficiency of photocatalysis due to the simple spatial symmetry inside the microreactor channel and among the individual channels. In addition, the bandgap of TiO2, ZnO, or other photocatalyst nanoparticles with symmetric crystal structure can be modified through doping or embedding. In this mini-review, a review of the reported continuous-flow photocatalytic microfluidic reactor is discussed from the perspective of both microreactor design and material engineering.

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Influence of Pixel Etching on Electrical and Electro-Optical Performances of a Ga-Free InAs/InAsSb T2SL Barrier Photodetector for Mid-Wave Infrared Imaging

Photonics ◽

10.3390/photonics8060194 ◽

2021 ◽

Vol 8 (6) ◽

pp. 194

Author(s):

Maxime Bouschet ◽

Ulises Zavala-Moran ◽

Vignesh Arounassalame ◽

Rodolphe Alchaar ◽

Clara Bataillon ◽

...

Keyword(s):

Dark Current ◽

Infrared Imaging ◽

Diffusion Length ◽

Lateral Diffusion ◽

Pixel Detector ◽

Dark Current Density ◽

Etching Depth ◽

Photo Response ◽

Wet Chemical ◽

Absorbing Layer

In this paper, the influence of etching depth on the dark current and photo-response of a mid-wave infrared Ga-free T2SL XBn pixel detector is investigated. Two wet chemical etching depths have been considered for the fabrication of a non-passivated individual pixel detector having a cut-off wavelength of 5 µm at 150 K. This study shows the strong influence of the lateral diffusion length of a shallow-etched pixel on the electro-optical properties of the device. The lowest dark current density was recorded for the deep-etched detector, on the order of 1 × 10−5 A/cm2 at 150 K and a bias operation equal to −400 mV. The corresponding quantum efficiency was measured at 60% (without anti-reflection coating) for a 3 µm thick absorbing layer. A comparison of experimental results obtained on the two kinds of etched pixels demonstrates the need for a deep-etching process combined with efficient passivation for FPA manufacturing.

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