Photothermal Investigation of Surfaces and Interfaces in Amorphous Silicon Films

1990 ◽  
Vol 192 ◽  
Author(s):  
G. Amato ◽  
L. Boarino ◽  
Giuliana Benedetto ◽  
R Spagnolo
Keyword(s):  
Amorphous Silicon ◽  
Density Of States ◽  
Theoretical Approach ◽  
Interference Fringe ◽  
Fringe Pattern ◽  
Experimental Results ◽  
Surface And Interface ◽  
Surfaces And Interfaces ◽  
Interference Fringe Pattern

ABSTRACTA method for the determination of surface and interface states is suggested, based on the observation of interference fringe pattern in photo-thermal spectra. Some experimental results are presented and interpreted by means of a theoretical approach. The method allows in most cases to get an evaluation of surface and interface density of states.

Determination of Hydrogen Density of States in Amorphous Silicon Using Fractional Evolution Experiments

1997 ◽  
Vol 467 ◽  
Author(s):  
A. J. Franz ◽  
W. B. Jackson ◽  
J. L. Gland
Keyword(s):  
Amorphous Silicon ◽  
Density Of States ◽  
Silicon Film ◽  
Mean Field ◽  
Frequency Factor ◽  
Silicon Films ◽  
Hydrogen Density ◽  
Heating And Cooling ◽  
Novel Method

ABSTRACTHydrogen plays an important role in the electronic behavior, structure and stability of amorphous silicon films. Therefore, determination of the hydrogen density of states (DOS) and correlation of the hydrogen DOS with the electronic film properties are important research goals. We have developed a novel method for determination of hydrogen DOS in silicon films, based on fractional evolution experiments. Fractional evolution experiments are performed by subjecting a silicon film to a series of linear, alternating heating and cooling ramps, while monitoring the hydrogen evolution rate. The fractional evolution data can be analyzed using two complementary memods, the fixed frequency factor approach and Arrhenius analysis. Using a rigorous, mean-field evolution model, we demonstrate the applicability of the two approaches to obtaining the hydrogen DOS in silicon films. We further validate both methods by analyzing experimental fractional evolution data foran amorphous silicon carbide film. Both types of analysis yield a similar double peaked density of states for the a-Si:C:H:D film.

An Equilibrium Based Mean-Field Model for Diffusion in Solids With a Distributed Density of States

1997 ◽  
Vol 469 ◽  
Author(s):  
A. J. Franz ◽  
J. L. Gland
Keyword(s):  
Amorphous Silicon ◽  
Density Of States ◽  
Chemical Potential ◽  
Energy Levels ◽  
Mean Field ◽  
Diffusion In Solids ◽  
Mean Field Model ◽  
Discrete Energy ◽  
Mobile Species

ABSTRACTDetermination of transport mechanisms and energetics in amorphous silicon presents an interesting modeling challenge. Transport in amorphous silicon films is likely to involve energetically distributed traps and mobile species, as in the case of hydrogen and electron diffusion. Detailed kinetic models using discrete energy levels have been developed, however, the density of states of the diffusing species in amorphous silicon is likely to be continuous and distributed, due to the amorphous nature of the films. We have developed a mean-field, equilibrium based model which utilizes a continuous density of states for the diffusing species. The transport in amorphous silicon is modeled as a function of a gradient in the quasi-chemical potential, rather than concentration, of the diffusing species. The model is applicable when the local equilibration processes are fast relative to the transport process. This approach is extremely numerically efficient, as well as flexible, allowing for modeling of tracer experiments, such as deuterium diffusion in a-Si:H films, and possible changes in density of states with time, temperature, and diffusing species concentration. We demonstrate the utility of the model by simulating hydrogen evolution from a-Si:H films.

Phase Retrieval Method of Single Interference Fringe Pattern Based on Shearing Interferometry

2015 ◽  
Vol 42 (12) ◽  
pp. 1208003
Author(s):  
郭媛 Guo Yuan ◽  
吴全 Wu Quan ◽  
陈小天 Chen Xiaotian ◽  
毛琦 Mao Qi ◽  
甄伟 Zhen Wei ◽  
...  
Keyword(s):  
Interference Fringe ◽  
Phase Retrieval ◽  
Fringe Pattern ◽  
Retrieval Method ◽  
Shearing Interferometry ◽  
Interference Fringe Pattern
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