Plasma Deposition of Silicon Clusters: A Way to Produce Silicon Thin Films With Medium-Range Order ?

1998 ◽  
Vol 507 ◽  
Author(s):  
P. Roca i Cabarrocas
Keyword(s):  
Thin Films ◽  
Transport Properties ◽  
Plasma Deposition ◽  
Random Network ◽  
Range Order ◽  
Homogeneous Material ◽  
Silicon Clusters ◽  
Medium Range Order ◽  
Silicon Thin Films ◽  
Medium Range

ABSTRACTThe growth of hydrogenated amorphous silicon films is often explained by the arrival of SiHx radicals on the substrate and the subsequent cross-linking reactions leading to an homogeneous material which can be described by a continuous random network. Here we summarize our recent Work on a new class of silicon thin films produced under plasma conditions where silicon clusters and radicals contribute to the deposition. The main aspects are: i) silicon clusters with sizes of the order of 1-5 nm are easily formed in silane plasmas; ii) these silicon clusters can contribute to the deposition and lead to the formation of films with medium-range order (“polymorphous silicon”); iii) despite their heterogeneity, the films have improved transport properties and stability with respect to a-Si:H. The excellent transport properties are confirmed by the achievement of stable single junction p-i-n solar cells with efficiencies close to 10 %.

The Structure of Ion-Implanted Amorphous Silicon

1998 ◽  
Vol 540 ◽  
Author(s):  
J. M. Gibson ◽  
J-Y. Cheng ◽  
P. Voyles ◽  
M.M.J. TREACY ◽  
D.C. Jacobson
Keyword(s):  
Amorphous Silicon ◽  
Network Model ◽  
Random Network ◽  
Amorphous Semiconductors ◽  
Range Order ◽  
Medium Range Order ◽  
Medium Range ◽  
Large Heat ◽  
Continuous Random Network ◽  
Ion Implanted

AbstractUsing fluctuation microscopy, we show that ion-implanted amorphous silicon has more medium-range order than is expected from the continuous random network model. From our previous work on evaporated and sputtered amorphous silicon, we conclude that the structure is paracrystalline, i.e. it possesses crystalline-like order which decays with distance from any point. The observation might pose an explanation for the large heat of relaxation that is evolved by ion-implanted amorphous semiconductors.

Hydrogen-Induced Reduction in Medium Range Order of a-Si Thin Films Observed using Fluctuation Electron Microscopy

2004 ◽  
Vol 10 (S02) ◽  
pp. 802-803
Author(s):  
Lakshmi Narayana Nittala ◽  
Sreenivas Jayaraman ◽  
Brent A Sperling ◽  
John R Abelson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Range Order ◽  
Medium Range Order ◽  
Medium Range ◽  
Fluctuation Electron Microscopy

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

scholarly journals Effect of medium range order on pulsed laser crystallization of amorphous germanium thin films

2016 ◽  
Vol 108 (22) ◽  
pp. 221906 ◽  
Author(s):  
T. T. Li ◽  
L. B. Bayu Aji ◽  
T. W. Heo ◽  
M. K. Santala ◽  
S. O. Kucheyev ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser ◽  
Range Order ◽  
Laser Crystallization ◽  
Amorphous Germanium ◽  
Medium Range Order ◽  
Medium Range

Local short- and medium-range order in amorphous transparent oxide thin films

2012 ◽  
Vol 18 (S2) ◽  
pp. 1458-1459
Author(s):  
A. Yan ◽  
B. Buchholz ◽  
R. Chang ◽  
V. Dravid ◽  
K.B. Borisenko ◽  
...  
Keyword(s):  
Thin Films ◽  
Range Order ◽  
Oxide Thin Films ◽  
Medium Range Order ◽  
Medium Range ◽  
Transparent Oxide

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Fluctuation Microscopy Studies of Medium-range Order Structures in Amorphous Tetrahedral Semiconductors

2000 ◽  
Vol 638 ◽  
Author(s):  
Xidong Chen ◽  
J. Murray Gibson ◽  
John Sullivan ◽  
Tom Friedmann ◽  
Paul Voyles
Keyword(s):  
Thermal Annealing ◽  
Random Network ◽  
Carbon Films ◽  
Range Order ◽  
Diamond Like Carbon ◽  
Medium Range Order ◽  
Microscopy Technique ◽  
Medium Range ◽  
Annealing Effects ◽  
Fluctuation Microscopy

AbstractWe applied fluctuation microscopy technique to study medium-range order in tetrahedral semiconductor materials, such as amorphous silicon, amorphous diamond-like carbon films. It is shown that this technique is very sensitive to local structure changes in the medium range order and promises solutions to open questions that cannot be answered by current techniques. For asdeposited amorphous germanium and silicon, we previously identified a fine-grain para-crystallite structure [1, 2], which will be relaxed into a lower-energy continuous random network structure after thermal annealing. With the same fluctuation microscopy technique, we however found that thermal annealing introduces medium-range order in amorphous diamond-like carbon films. Future studies will be focused on modeling and systematic exploration of annealing effects.

scholarly journals Dual Cluster Model for Medium-Range Order in Metallic Glasses

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1840
Author(s):  
Masato Shimono ◽  
Hidehiro Onodera
Keyword(s):  
Network Structure ◽  
Metallic Glasses ◽  
Random Network ◽  
Alloy System ◽  
Md Simulations ◽  
Range Order ◽  
Size Difference ◽  
Medium Range Order ◽  
Liquid Phases ◽  
Medium Range

The atomic structure of medium-range order in metallic glasses is investigated by using molecular dynamics (MD) simulations. Glass formation processes were simulated by rapid cooling from liquid phases of a model binary alloy system of different-sized elements. Two types of short-range order of atomic clusters with the five-fold symmetry are found in glassy phases: icosahedral clusters (I-clusters) formed around the smaller-sized atoms and Frank–Kasper clusters (i.e., Z14, Z15, and Z16 clusters (Z-clusters)) formed around the bigger-sized atoms. Both types of clusters (I-and Z-clusters) are observed even in liquid phases and the population of them goes up as the temperature goes down. A considerable atomic size difference between alloying elements would enhance the formation of both the I- and Z-clusters. In glassy phases, the I- and Z-clusters are mutually connected to form a complicated network, and the network structure becomes denser as the structural relaxation goes on. In the network, the medium-range order is mainly constructed by the volume sharing type connection between I- and Z-clusters. Following Nelson’s disclination theory, the network structure can be understood as a random network of Z-clusters, which is complimentarily surrounded by another type of network formed by I-clusters.

Fluctuation Electron Microscopy Study of Medium-Range Packing Order in Ultrastable Indomethacin Glass Thin Films

2015 ◽  
Vol 1757 ◽  
Author(s):  
L. He ◽  
A. Gujral ◽  
M. D. Ediger ◽  
P. M. Voyles
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Beam Current ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Range Order ◽  
Total Electron ◽  
Medium Range Order ◽  
Medium Range ◽  
Fluctuation Electron Microscopy

ABSTRACTWe have used fluctuation electron microscopy (FEM) to measure the medium range order in the molecular packing of 40 nm thick indomethacin glass films. Vapor deposition of indomethacin can create glasses with extraordinary kinetic stability and high density. We find peaks in the FEM variance at diffraction vector magnitudes between 0.03 and 0.09 Å-1, corresponding to intermolecular packing distances of 1-3 nm. FEM experiments were performed with a 13 nm diameter electron probe, so these data are sensitive to medium-range order in intermolecular packing. The FEM variance from an indomethacin glass with normal stability cooled from the liquid is significantly smaller than the variance from the ultrastable glass, suggesting that ultrastable glass is more structurally heterogeneous at a 13 nm length scale. A dose of ∼7×105 e-/nm2 with a very low beam current of ∼ 2.5 pA at 200 kV was used to minimize electron beam damage to the sample, and the average electron diffraction from the sample is unchanged at total electron doses fourteen times larger than required for a FEM experiment. These preliminary results on medium-range order in molecular glasses suggest that we may be able to provide insight into the structural differences between the remarkable ultrastable thin films and ordinary glasses.

Observations of structural order in ion-implanted amorphous silicon

2001 ◽  
Vol 16 (11) ◽  
pp. 3030-3033 ◽  
Author(s):  
Ju-Yin Cheng ◽  
J. M. Gibson ◽  
D. C. Jacobson
Keyword(s):  
Electron Microscopy ◽  
Amorphous Silicon ◽  
Random Network ◽  
Dark Field ◽  
Range Order ◽  
Length Scale ◽  
Medium Range Order ◽  
Medium Range ◽  
Fluctuation Electron Microscopy ◽  
Ion Implanted

Medium-range order in ion-implanted amorphous silicon has been observed using fluctuation electron microscopy. In fluctuation electron microscopy, variance of dark-field image intensity contains the information of high-order atomic correlations, primarily in medium-range order length scale (1–3 nm). Thermal annealing greatly reduces the order and leaves a random network. It appears that the free energy change previously observed on relaxation may therefore be associated with randomization of the network. In this paper, we discuss the origin of the medium-range order during implantation, which can be interpreted as a paracrystalline state, that is, a disordered network enclosing compacts of highly topologically ordered grains on the length scale of 1–3 nm with significant strain fields.

Sign in / Sign up

Export Citation Format

Share Document