Extended-range order in tetrahedral amorphous semiconductors: The case of amorphous silicon

Dahal, Devilal; Elliott, S. R.; Biswas, Parthapratim

doi:10.1103/physrevb.105.115203

Cited by 6 publications

(4 citation statements)

References 48 publications

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“…% H, are presented in Fig.4. The positions of the first Si-Si peak at 2.37 Å and the first Si-H peak at 1.51 Å in the plots are consistent with the results obtained by other researchers and experiments[52,55,56].…”

supporting

confidence: 92%

Ab Initio Study of the Structure and Properties of Amorphous Silicon Hydride from Acceleratedmolecular Dynamics Simulations

Atta-Fynn,

Rathi,

Arya

et al. 2023

Preprint

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supporting

confidence: 92%

Ab Initio Study of the Structure and Properties of Amorphous Silicon Hydride from Acceleratedmolecular Dynamics Simulations

Atta-Fynn,

Rathi,

Arya

et al. 2023

Preprint

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“…To understand the dynamics of our organic memristors, a fundamental aspect is to comprehend the charge transport mechanism within the device structure. Numerous device frameworks and mechanisms have been proposed to unravel the memory effects of the devices, , which include the transformation of the macromolecular domains from amorphous to extended-ordering, , formation of conduction channel between the two contacts, , intramolecular rotation of the molecular complexes, , and by coinciding the tails of valence and conduction bands . Nevertheless, the efficacy of our memristors is dependent on and influenced by the Al-AlO x nanoclusters.…”

Section: Resultsmentioning

confidence: 99%

High-Density, Nonvolatile, Flexible Multilevel Organic Memristor Using Multilayered Polymer Semiconductors

Sharma,

Pandey,

Nagamatsu

et al. 2024

ACS Appl. Mater. Interfaces

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Nonvolatile organic memristors have emerged as promising candidates for next-generation electronics, emphasizing the need for vertical device fabrication to attain a high density. Herein, we present a comprehensive investigation of highperformance organic memristors, fabricated in crossbar architecture with PTB7/Al-AlO x -nanocluster/PTB7 embedded between Al electrodes. PTB7 films were fabricated using the Unidirectional Floating Film Transfer Method, enabling independent uniform film fabrication in the Layer-by-Layer (LbL) configuration without disturbing underlying films. We examined the charge transport mechanism of our memristors using the Hubbard model highlighting the role of Al-AlO x -nanoclusters in switching-on the devices, due to the accumulation of bipolarons in the semiconducting layer. By varying the number of LbL films in the device architecture, the resistance of resistive states was systematically altered, enabling the fabrication of novel multilevel memristors. These multilevel devices exhibited excellent performance metrics, including enhanced memory density, high on−off ratio (>10 8 ), remarkable memory retention (>10 5 s), high endurance (87 on−off cycles), and rapid switching (∼100 ns). Furthermore, flexible memristors were fabricated, demonstrating consistent performance even under bending conditions, with a radius of 2.78 mm for >10 4 bending cycles. This study not only demonstrates the fundamental understanding of charge transport in organic memristors but also introduces novel device architectures with significant implications for high-density flexible applications.

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“…Later studies, with increasingly fast computers, extended system sizes to hundreds of thousands of atoms with empirical potentials. [18][19][20] Equally, quantum-mechanically based (density-functional theory, DFT) MD studies on much smaller systems have provided important insights. [22][23][24] However, predictive DFT simulations of a-Si beyond the few-nm length scale remain out of reach, due to the long simulation times required and the cubic scaling of computational cost with system size.…”

Section: Introductionmentioning

confidence: 99%

“…The large concentration of coordination defects in the models obtained this way (≈20 %) permitted a discussion of the average structure of N =5 defects, as well as an analysis of the energetics predicted by the potential. Later studies, with increasingly fast computers, extended system sizes to hundreds of thousands of atoms with empirical potentials [18–20] . Equally, quantum‐mechanically based (density‐functional theory, DFT) MD studies on much smaller systems have provided important insights [22–24] .…”

Section: Introductionmentioning

confidence: 99%

Understanding Defects in Amorphous Silicon with Million‐Atom Simulations and Machine Learning

Morrow,

Ugwumadu,

Drabold

et al. 2024

Angewandte Chemie

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The structure of amorphous silicon (a‐Si) is widely thought of as a fourfold‐connected random network, and yet it is defective atoms, with fewer or more than four bonds, that make it particularly interesting. Despite many attempts to explain such “dangling‐bond” and “floating‐bond” defects, respectively, a unified understanding is still missing. Here, we use advanced computational chemistry methods to reveal the complex structural and energetic landscape of defects in a‐Si. We study an ultra‐large‐scale, quantum‐accurate structural model containing a million atoms, and thousands of individual defects, allowing reliable defect‐related statistics to be obtained. We combine structural descriptors and machinelearned atomic energies to develop a classification of the different types of defects in a‐Si. The results suggest a revision of the established floating‐bond model by showing that fivefold‐bonded atoms in a‐Si exhibit a wide range of local environments—analogous to fivefold centers in coordination chemistry. Furthermore, it is shown that fivefold (but not threefold) coordination defects tend to cluster together. Our study provides new insights into one of the most widely studied amorphous solids, and has general implications for understanding defects in disordered materials beyond silicon alone.

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Extended-range order in tetrahedral amorphous semiconductors: The case of amorphous silicon

Cited by 6 publications

References 48 publications

Ab Initio Study of the Structure and Properties of Amorphous Silicon Hydride from Acceleratedmolecular Dynamics Simulations

Ab Initio Study of the Structure and Properties of Amorphous Silicon Hydride from Acceleratedmolecular Dynamics Simulations

High-Density, Nonvolatile, Flexible Multilevel Organic Memristor Using Multilayered Polymer Semiconductors

Understanding Defects in Amorphous Silicon with Million‐Atom Simulations and Machine Learning

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