scholarly journals Examining normal modes as fundamental heat carriers in amorphous solids: The case of amorphous silicon

2021 ◽  
Vol 130 (5) ◽  
pp. 055101
Author(s):  
Jaeyun Moon
Keyword(s):  
Amorphous Silicon ◽  
Normal Modes ◽  
Amorphous Solids ◽  
Heat Carriers

Low Temperature Vibrational Properties of Amorphous Silicon

1998 ◽  
Vol 507 ◽  
Author(s):  
R. S. Crandall ◽  
E. Iwaniczko ◽  
A. H. Mahan ◽  
X. Liu ◽  
R.O. Pohl
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Internal Friction ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Amorphous Solids ◽  
Vibrational Properties ◽  
Deposition Method ◽  
Hot Wire

ABSTRACTWe present internal friction and shear modulus measurements of amorphous silicon (a-Si) and germanium (a-Ge) films. The temperature independent plateau in internal friction below 10 K, common to all amorphous solids, also exists in these films. However, its magnitude which depends critically on the deposition method is smaller than found for all other amorphous solids. In particular, hydrogenated a-Si with about 1 at. % H prepared by hot-wire chemical-vapor-deposition leads to an internal friction nearly three orders of magnitude smaller than observed for all other amorphous solids. The internal friction increases after the hydrogen is removed by effusion.

New Results on the Microstructure of Amorphous Silicon as Observed by Internal Friction

1997 ◽  
Vol 467 ◽  
Author(s):  
R. S. Crandall ◽  
A. H. Mahan ◽  
E. Iwaniczko ◽  
K. M. Jones ◽  
X. Liu ◽  
...  
Keyword(s):  
Internal Friction ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Electron Beam Evaporation ◽  
Hot Wire ◽  
Si Films ◽  
Hydrogenated Amorphous

ABSTRACTWe have measured the low temperature internal friction (Q−1) of amorphous silicon (a-Si) films. Electron-beam evaporation leads to the well-known temperature-independent plateau common to all amorphous solids. For hydrogenated amorphous silicon (a-Si:H) with about 1 at.% H produced by hot wire chemical vapor deposition, however, the value of is over two hundred times smaller than for e-beam a-Si. This is the first observation of an amorphous solid without any significant low energy excitations. This finding offers the opportunity to study amorphous solids containing controlled densities of tunneling defects, and thus to explore their nature.

Machine learning reveals the complexity of dense amorphous silicon

Nature ◽  
2021 ◽  
Vol 589 (7840) ◽  
pp. 22-23
Author(s):  
Paul F. McMillan
Keyword(s):  
Machine Learning ◽  
Amorphous Silicon

Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira
Keyword(s):  
Amorphous Silicon ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Deposition Process ◽  
Large Area ◽  
Sidewall Roughness ◽  
Sensing Applications ◽  
Fabrication Defects ◽  
The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

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