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.

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.

Mechanical Spectroscopy Study on the Light Soaking Effect on Hydrogenated Amorphous Silicon

2012 ◽  
Vol 184 ◽  
pp. 416-421 ◽  
Author(s):  
H. Mizubayashi ◽  
I. Sakata ◽  
H. Tanimoto
Keyword(s):  
Internal Friction ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Wide Distribution ◽  
Activation Energies ◽  
Mechanical Spectroscopy ◽  
Induced Changes ◽  
Mild Temperature ◽  
Hydrogenated Amorphous

For hydrogenated amorphous silicon (a-Si:H) films deposited at temperatures between 423 K and 623 K (a-Si:H423Kand so on), the light-induced changes in the internal friction between 80 K and 400 K were studied. The internal friction is associated with H2motion in microvoid networks, and shows the mild temperature dependence between about 80 K and 300 K (Q-180-300K) and the almost linear increase above 300 K (Q-1>300K). BothQ-180-300KandQ-1>300Kdecrease with increasing the deposition temperature, and show the mild temperature dependence ina-Si:H623K. The white light soaking with 100 mW/cm2(WLS100and so on) below 300 K caused a change inQ-180-300Kand no changes inQ-1>300K, respectively, and the light-induced changes inQ-180-300Krecovered after annealing at 423 K. The wide distribution of activation energies for H2motions between microvoids indicate that most of neighboring microvoids are connected through windows, i.e., the microvoid networks are existing ina-Si:H, and the spatially loose or solid structures are responsible for the low or high activation energies for the H2motion between microvoids, respectively. Furthermore, the light-induced hydrogen evolution (LIHE) was observed for WLS200to WLS400in a vacuum between 400 and 500 K, resulting in the disappearance of the internal friction due to the H2motion in the microvoid network.

Thermopower and 1/f Noise Measurements in Amorphous Silicon-Carbon Alloys

1995 ◽  
Vol 377 ◽  
Author(s):  
H. M. Dyalsingh ◽  
G. M. Khera ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Power Spectra ◽  
Carbon Films ◽  
Noise Power ◽  
Mobility Edge ◽  
Silicon Carbon ◽  
Noise Measurements ◽  
Noise Statistics ◽  
Hydrogenated Amorphous ◽  
Q Function

ABSTRACTThermopower, conductivity and 1/f noise measurements have been performed on a series of n-type doped hydrogenated amorphous silicon carbon films that are prepared with varying gas phase concentrations of CH4. The increased disorder at the mobility edge associated with alloying is characterized by the Q-function, which is obtained by combining thermopower and conductivity measurements, and is also reflected in the noise power spectra and noise statistics.

Sign in / Sign up

Export Citation Format

Share Document