Telegraph Noise as A Probe of Microscopic Hydrogen Motion in Amorphous Silicon

1995 ◽  
Vol 377 ◽  
Author(s):  
Lisa M. Lust ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Diffusion Processes ◽  
Switching Noise ◽  
Resistor Network ◽  
Network Support ◽  
Conductance Fluctuations ◽  
Telegraph Noise ◽  
Current Filaments ◽  
Hydrogenated Amorphous ◽  
Dynamical Percolation

ABSTRACTTime traces of conductance fluctuations in the co-planar current of hydrogenated amorphous silicon (a-Si:H) display sharp jumps between discrete resistance levels, termed random telegraph switching noise (RTSN). Measurements of the temperature dependence and effects of light soaking of the RTSN in n-type doped a-Si:H are reported. The rise times between the two level fluctuators yield activation energies and attempt to hop frequencies for microscopic hydrogen motion which agree with those obtained from NMR experiments. Computer simulations of a dynamical percolation random resistor network support the suggestion that the RTSN arises from local diffusion processes altering the conductance of inhomogeneous current filaments.

1 / F Noise Measurements of Interacting Current Filaments in Hydrogenated Amorphous Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
C.E. Parman ◽  
N.E. Israeloff ◽  
J. Fan ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Power Spectra ◽  
Noise Power ◽  
Switching Noise ◽  
Scale Invariant ◽  
Noise Sources ◽  
Noise Measurements ◽  
Current Filaments ◽  
Hydrogenated Amorphous

The coplanar current in n-lype doped hydrogenated amorphous silicon (a-Si:H) displays random telegraph switching noise, indicating the presence of inhomogeneous current filaments whose conductance varies with time. There are strong correlations of the 1/f noise power spectra across differing frequency octaves which are much larger than expected if the magnitudes of the fluctuators are varied in parallel. The scale invariant second spectra and the temperature dependence of the spectral slope indicate that hydrogen motion is involved in the cooperative dynamics between noise sources. A model is described wherein the properties of the current filaments are modulated by hydrogen-hydrogen interactions which are mediated by the Si strain fields.

Conductance fluctuations in doped hydrogenated amorphous silicon

1993 ◽  
Vol 47 (19) ◽  
pp. 12578-12589 ◽  
Author(s):  
C. E. Parman ◽  
N. E. Israeloff ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Conductance Fluctuations ◽  
Hydrogenated Amorphous

On the Role of Surface Diffusion and Its Relation to the Hydrogen Incorporation During Hydrogenated Amorphous Silicon Growth

2003 ◽  
Vol 762 ◽  
Author(s):  
A.H.M. Smets ◽  
W.M.M. Kessels ◽  
M.C.M. van de Sanden
Keyword(s):  
Activation Energy ◽  
Amorphous Silicon ◽  
Surface Diffusion ◽  
Diffusion Processes ◽  
Growth Parameters ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogen Incorporation ◽  
Silicon Growth ◽  
Surface Diffusion Processes ◽  
Hydrogenated Amorphous

AbstractThe incorporation of hydrogen in vacancies and at void surfaces during hydrogenated amorphous silicon growth from a remote expanding thermal plasma (ETP) is systematically studied by variation of the mass growth flux Γa-Si:H and substrate temperatureTsub. An evident relation between the void incorporation and the growth parameters Γa-Si:H andTsubhas been observed. We speculate on a possible relation with the surface diffusion processes during deposition. An activation energy for surface diffusion during a-Si:H growth of 0.8-1.1 eV is obtained using this assertion, similar to the activation energy deduced from surface roughness evolution studies. For compact films hydrogen is predominantly present at vacancies, and a possible relation with the hydrogen removal mechanism during deposition is discussed.

1/f Noise and Thermal Equilibration Effects in Hot Wire Deposited Amorphous Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
G. M. Khera ◽  
J. Kakalios ◽  
Q. Wang ◽  
E. Iwaniczko
Keyword(s):  
Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Thermal Equilibration ◽  
Silicon Thin Films ◽  
Conductance Fluctuations ◽  
Non Gaussian ◽  
Noise Statistics ◽  
Hydrogenated Amorphous

AbstractMeasurements of the conductance fluctuations and thermal equilibration of the dark conductivity of a series of undoped hydrogenated amorphous silicon thin films synthesized by Hot-Wire Chemical Vapor Deposition (HWCVD), with hydrogen contents varying from less than one to twelve atomic percent are reported. The spectral density of the conductance fluctuations varies inversely with frequency f and is dependent upon hydrogen concentration; the 1/f noise statistics are non- Gaussian, indicating correlated fluctuators as is observed in PECVD a-Si:H. These results indicate that aspects of electronic transport and defect dynamics in HWCVD films are similar to those in PECVD a-Si:H films.

Non-Gaussian 1 / f Noise and Conductance Fluctuations in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
C. E. Parman ◽  
N. E. Israeloff ◽  
J. Kakalios
Keyword(s):  
Spectral Analysis ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Current Fluctuations ◽  
Noise Power ◽  
Effective Volume ◽  
Conductance Fluctuations ◽  
Cooperative Dynamics ◽  
Non Gaussian ◽  
Hydrogenated Amorphous

ABSTRACTStatistical analysis of the 1/f noise power spectrum of co-planar current fluctuations in n-type doped hydrogenated amorphous silicon (a-Si:H) find that the noise arises from a small number of correlated fluctuators. The noise power displays a complicated time dependence with the noise power changing in both magnitude and as a function of frequency. Spectral analysis of these noise power fluctuations display an approximate 1/f frequency dependence. These results are surprising given the effective volume (∼10-7 cm3) of the sample, and indicate that cooperative dynamics govern conductance fluctuations in a-Si:H.

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