scholarly journals Carrier Transport in Ultra-Thin Nano/Polycrystalline Silicon Films and Nanowires

2001 ◽  
Vol 664 ◽  
Author(s):  
Toshio Kamiya ◽  
Yong T. Tan ◽  
Yoshikazu Furuta ◽  
Hiroshi Mizuta ◽  
Zahid A.K. Durrania ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Polycrystalline Silicon ◽  
Carrier Transport ◽  
Crystalline Silicon ◽  
Thermionic Emission ◽  
Nanocrystalline Silicon ◽  
Silicon Films ◽  
Si Nanowires ◽  
Potential Barriers ◽  
Boundary Potential

ABSTRACTCarrier transport was investigated in two different types of ultra-thin silicon films, polycrystalline silicon (poly-Si) films with large grains > 20 nm in size and hydrogenated nanocrystalline silicon (nc-Si:H) films with grains 4 nm – 8 nm in size. It was found that there were local non-uniformities in grain boundary potential barriers in both types of films. Single-electron charging effects were observed in 30 nm × 30 nm nanowires fabricated in 30 nm-thick nc-Si:H films, where the electrons were confined in crystalline silicon grains encapsulated by amorphous silicon. In contrast, the poly-Si nanowires of similar dimensions showed thermionic emission over the grain boundary potential barriers formed by carrier trapping in grain boundary defects.

Effect of grain alignment on lateral carrier transport in aligned-crystalline silicon films on polycrystalline substrates

2007 ◽  
Vol 22 (4) ◽  
pp. 821-825 ◽  
Author(s):  
Woong Choi ◽  
Alp T. Findikoglu ◽  
Manuel J. Romero ◽  
Mowafak Al-Jassim
Keyword(s):  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Carrier Transport ◽  
Crystalline Silicon ◽  
Silicon Films ◽  
Dangling Bond ◽  
Grain Alignment ◽  
Bond Density ◽  
Polycrystalline Silicon Films ◽  
Trapping Sites

We report the studies on the effect of grain alignment on lateral carrier transport in nominally 〈001〉-oriented aligned-crystalline silicon (ACSi) films on polycrystalline substrates. With improving grain alignment, energy barrier height at the grain boundaries was reduced from 150 to less than 1 meV, and both conductivity and Hall mobility became less sensitive to hydrogen passivation. This suggests that the dangling bonds in ACSi films are a major source of trapping sites, and that they become less dominant with improving grain alignment. These results demonstrate that improving grain alignment enhances the lateral carrier transport in small-grained (≤1 μm) polycrystalline silicon films, by reducing dangling bond density at the grain boundaries.

scholarly journals Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 759
Author(s):  
Luana Mazzarella ◽  
Anna Morales-Vilches ◽  
Lars Korte ◽  
Rutger Schlatmann ◽  
Bernd Stannowski
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Carrier Transport ◽  
Silicon Oxide ◽  
Short Circuit ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Silicon Films ◽  
Two Phase ◽  
Nanocrystalline Silicon Films

Doped hydrogenated nanocrystalline (nc-Si:H) and silicon oxide (nc-SiOx:H) materials grown by plasma-enhanced chemical vapor deposition have favourable optoelectronic properties originated from their two-phase structure. This unique combination of qualities, initially, led to the development of thin-film Si solar cells allowing the fabrication of multijunction devices by tailoring the material bandgap. Furthermore, nanocrystalline silicon films can offer a better carrier transport and field-effect passivation than amorphous Si layers could do, and this can improve the carrier selectivity in silicon heterojunction (SHJ) solar cells. The reduced parasitic absorption, due to the lower absorption coefficient of nc-SiOx:H films in the relevant spectral range, leads to potential gain in short circuit current. In this work, we report on development and applications of hydrogenated nanocrystalline silicon oxide (nc-SiOx:H) from material to device level. We address the potential benefits and the challenges for a successful integration in SHJ solar cells. Finally, we prove that nc-SiOx:H demonstrated clear advantages for maximizing the infrared response of c-Si bottom cells in combination with perovskite top cells.

scholarly journals Nanoscale Tuning of Grain Boundary Potential Barriers in Doped Strontium Titanate

2003 ◽  
Vol 9 (S02) ◽  
pp. 672-673
Author(s):  
Pradyumna L. Prabhumirashi ◽  
Andrew R. Lupini ◽  
Stephen J. Pennycook ◽  
Vinayak P. Dravid
Keyword(s):  
Grain Boundary ◽  
Strontium Titanate ◽  
Potential Barriers ◽  
Boundary Potential

Models for Electronic Conduction Across Ceramic Grain Boundaries

1985 ◽  
Vol 60 ◽  
Author(s):  
L. C. Burton
Keyword(s):  
Grain Boundary ◽  
Space Charge ◽  
Boundary Behavior ◽  
High Resistivity ◽  
Potential Barriers ◽  
Ohmic Behavior ◽  
Boundary Potential ◽  
Electronic Current ◽  
Grain Width ◽  
Limited Diffusion

AbstractElectronic current flow over grain boundary potential barriers for low resistance grains is first reviewed. It is then shown that if the resistance of the grains increases and/or grain size is reduced, the grains may be totally depleted of mobile charge. The grain boundary barrier is thus reduced to (D/2W)2 of its original large grain value, D being grain width and W the full space charge width. For high resistivity grains satisfying the relation D ≪ 2W, the conduction band becomes essentially flat. Phenomena formerly caused by grain boundary potential barriers (varistor and PTC effects seen in semiconducting ceramic) will be greatly reduced, or eliminated.Commercial COG and X7R MLC capacitors exhibit a transition from super-ohmic to ohmic behavior at high voltages, paralleling the behavior of the varistor. Two possible mechanisms that could account for this are varistor-like grain boundary behavior, or space charge limited diffusion current.

Carrier transport in polycrystalline silicon films deposited by a layer‐by‐layer technique

1994 ◽  
Vol 76 (8) ◽  
pp. 4728-4733 ◽  
Author(s):  
Deyan He ◽  
Naoto Okada ◽  
Charles M. Fortmann ◽  
Isamu Shimizu
Keyword(s):  
Polycrystalline Silicon ◽  
Carrier Transport ◽  
Silicon Films ◽  
Layer By Layer ◽  
Layer Technique ◽  
Polycrystalline Silicon Films ◽  
Layer By Layer Technique

Preferential 〈220〉 crystalline growth in nanocrystalline silicon films from 27.12 MHz SiH4 plasma for applications in solar cells

RSC Advances ◽  
2015 ◽  
Vol 5 (67) ◽  
pp. 54011-54018 ◽  
Author(s):  
Praloy Mondal ◽  
Debajyoti Das
Keyword(s):  
Solar Cells ◽  
Grain Boundary ◽  
Grain Growth ◽  
Crystal Orientation ◽  
Nanocrystalline Silicon ◽  
Silicon Films ◽  
Random Nucleation ◽  
Crystalline Growth ◽  
Nanocrystalline Silicon Films

Si-ncs are generally of 〈111〉 crystal orientation from random nucleation within poly-H network at grain-boundary, while Si ultra-ncs preferably harvest 〈220〉 alignment due to thermodynamically preferred grain growth by mono-H bonding at the boundary.

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