Medium-range order in pyrolyzed carbon films: Structural evidence related to metal–insulator transition

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.

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Abnormal current–voltage characteristics and metal–insulator transition of amorphous Fe-doped carbon films on Si substrates

Physica B Condensed Matter ◽

10.1016/j.physb.2008.05.004 ◽

2008 ◽

Vol 403 (19-20) ◽

pp. 3434-3438

Author(s):

Liubin Huang ◽

Lanzhong Hao ◽

Keyou Yan ◽

Qingzhong Xue

Keyword(s):

Carbon Films ◽

Insulator Transition ◽

Metal Insulator Transition ◽

Metal Insulator ◽

Si Substrates ◽

Current Voltage ◽

Current Voltage Characteristics

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Metal–insulator transition in iodinated amorphous conducting carbon films

Carbon ◽

10.1016/j.carbon.2004.04.019 ◽

2004 ◽

Vol 42 (11) ◽

pp. 2133-2137 ◽

Cited By ~ 15

Author(s):

Latha Kumari ◽

S.V Subramanyam ◽

S Eto ◽

K Takai ◽

T Enoki

Keyword(s):

Carbon Films ◽

Insulator Transition ◽

Metal Insulator Transition ◽

Metal Insulator

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Short range order and the metal-insulator transition in disordered systems

Solid State Communications ◽

10.1016/0038-1098(73)90864-8 ◽

1973 ◽

Vol 12 (12) ◽

pp. 1275-1278 ◽

Cited By ~ 15

Author(s):

D.C. Licciardello ◽

E.N. Economou

Keyword(s):

Disordered Systems ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Insulator Transition ◽

Metal Insulator Transition ◽

Metal Insulator

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Medium-Range Order Structures of Amorphous Diamond-Like Carbon Films

MRS Proceedings ◽

10.1557/proc-675-w12.1.1 ◽

2001 ◽

Vol 675 ◽

Cited By ~ 1

Author(s):

Xidong Chen ◽

J. Murray Gibson ◽

John Sullivan ◽

Tom Friedmann

Keyword(s):

Correlation Function ◽

Density Functional ◽

Dark Field ◽

Carbon Films ◽

Range Order ◽

Diamond Like Carbon ◽

Medium Range Order ◽

Medium Range ◽

Order Structures ◽

Body Correlation

ABSTRACTIn this paper, we have studied medium-range order structures in amorphous diamond-like carbon films with fluctuation microscopy. Medium-range order structures are quantified by a specific form of a general four-body correlation. We name this function as a pair-pair alignment correlation function. By analyzing speckle dark-field images taken over different areas as a function of momentum transfer in reciprocal space, we measured the pair-pair alignment correlation function for both thermally annealed samples and unannealed samples. We have found that thermal annealing introduces medium-range order in amorphous diamond-like carbon films, causing more pairs of atoms to be aligned. These results agree with density-functional simulations. Larger-scale simulations will be needed to fully understand our experimental results.

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