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.

Light Induced Changes in the Non-Gaussian Noise Statistics in Doped Hydrogenated Amorphous Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
J. Fan ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Gaussian Noise ◽  
Hydrogenated Amorphous Silicon ◽  
Noise Power ◽  
Defect Creation ◽  
Non Gaussian ◽  
Noise Statistics ◽  
Induced Changes ◽  
Many Body Interactions ◽  
Hydrogenated Amorphous

The power spectrum of coplanar current fluctuations in n-type doped hydrogenated amorphous silicon (a-Si:H) has been measured before and after metastable defect creation by light soaking. The average magnitude and spectral slope of the 1/f noise are not affected by illumination, however significant changes in the higher order statistics are observed. Associated with the decrease of conductivity upon light soaking (the Staebler-Wronski effect), there is a decrease in the correlation of the noise power which characterize the non-Gaussian noise in the annealed state. These changes in the noise statistics are reversible by annealing. The light-induced changes in the non-Gaussian statistics provide experimental support for models of light induced defect creation which involve long-ranged and many body interactions.

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

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.

1/f Noise Measurements of Hydrogenated Amorphous Silicon-Carbon Alloys

1994 ◽  
Vol 336 ◽  
Author(s):  
H. M. Dyalsingh ◽  
G. M. Khera ◽  
J. Kakalios ◽  
C. C. Tsai ◽  
R. A. Street
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Mobility Edge ◽  
Silicon Carbon ◽  
Noise Measurements ◽  
Gaussian Statistics ◽  
Non Gaussian ◽  
P Type ◽  
Hydrogenated Amorphous ◽  
Carbon Concentrations

ABSTRACTMeasurements of the optical, electronic and 1/f noise properties for a series of n-type doped hydrogenated amorphous silicon carbide thin films with varying gas phase concentrations of CH4 are described. The increase in the optical absorption edge of the n-type a-SiCx:H films with the addition of carbon is slower than in p-type films. Studies of the variation in the non-Gaussian statistics which characterize the 1/f noise indicate that the disorder at the mobility edge is greater for films with higher carbon concentrations.

1 / f Noise in Hydrogenated Amorphous Silicon

1991 ◽  
Vol 219 ◽  
Author(s):  
C. Parman ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Power Law ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Current Fluctuations ◽  
Surprising Result ◽  
Frequency Range ◽  
Temperature Dependent ◽  
Power Law Exponent ◽  
Hydrogenated Amorphous

ABSTRACTMeasurements of co-planar current fluctuations in n-type doped hydrogenated amorphous silicon (a-Si:H) find that the spectral density of the noise accurately obeys a 1/f frequency dependence over the frequency range of 1 Hz to 1 kHz for temperatures ranging from room temperature to 450K. The noise displays a power law dependence on the d.c. curent passing through the sample, with a temperature dependent power law exponent. In addition, the resistance of the a-Si:H as a function of time displays switching phenomena; a surprising result given the effective volume ( ∼10-6 cm3) of the sample.

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