ac photoconductivity of hydrogenated amorphous silicon: Influence of long-range potential fluctuations

2002 ◽  
Vol 65 (16) ◽  
Author(s):  
K. Shimakawa ◽  
Ashtosh Ganjoo
Keyword(s):  
Amorphous Silicon ◽  
Long Range ◽  
Hydrogenated Amorphous Silicon ◽  
Potential Fluctuations ◽  
Range Potential ◽  
Hydrogenated Amorphous

LONG-RANGE FLUCTUATIONS OF RANDOM POTENTIAL LANDSCAPE AS A MECHANISM OF 1/f NOISE IN HYDROGENATED AMORPHOUS SILICON

2005 ◽  
Vol 05 (03) ◽  
pp. L443-L456
Author(s):  
BORIS V. FINE ◽  
JEROEN P. R. BAKKER ◽  
JAAP I. DIJKHUIS
Keyword(s):  
Amorphous Silicon ◽  
Long Range ◽  
Noise Intensity ◽  
Broad Class ◽  
Hydrogenated Amorphous Silicon ◽  
Low Frequency ◽  
Noise Spectrum ◽  
Current Flows ◽  
Charged Defects ◽  
Hydrogenated Amorphous

We describe a mechanism that links the long-range potential fluctuations induced by charged defects to the low-frequency resistance noise widely known as 1/fnoise. This mechanism is amenable to the first principles microscopic calculation of the noise spectrum, which includes the absolute noise intensity. We have performed such a calculation for the thin films of hydrogenated amorphous silicon ( a-Si:H ) under the condition that current flows perpendicular to the plane of the films, and have found a very good agreement between the theoretical noise intensity and the measured one. The mechanism described is quite general. It should be present in a broad class of systems containing poorly screened charged defects.

Defect Thermodynamics, Inhomogeneity, and the Density of Gap States in Hydrogenated Amorphous Silicon

1990 ◽  
Vol 192 ◽  
Author(s):  
Howard M. Branz ◽  
Marvin Silver
Keyword(s):  
Amorphous Silicon ◽  
Defect Formation ◽  
Numerical Solutions ◽  
Correlation Energy ◽  
Hydrogenated Amorphous Silicon ◽  
Level Energy ◽  
Dangling Bond ◽  
Potential Fluctuations ◽  
Material Inhomogeneity ◽  
Hydrogenated Amorphous

ABSTRACTA new hydrogenated amorphous silicon (a-Si:H) density of states (d.O.s.) in+cluding the transition levels of both neutral (T3o) and charged (T3+ and T3−) dangling-bond defects is proposed. We derive closed-form and numerical solutions for the d.o.s. from a thermodynamic equilibrium theory of defect concentrations in which material inhomogeneity is assumed to give rise to ∼1020 cm−3 of electrostatic potential fluctuations. The connection between thermodynamic transition level energy and defect formation energy implicit in this and other “defect pool” models is included explicitly in the calculation. We calculate the d.o.s. for a range of parameters and for different values of Fermi energy. We apply the calculated d.o.s. to explain and unify various experimental results in a-Si:H. In particular, we reconcile recent depletion-width-modulated ESR data with the near-perfect Curie law T-dependence of the dangling-bond spin density observed by several groups. It is seen +that the depletion results in roughly equal numbers of T3−T3–>° and T3°–>T3+ transitions despite the positive value of effective correlation energy. We also discuss possible sources of the short-to-medium range potential fluctuations in amorphous silicon.

Potential fluctuations in intrinsic hydrogenated amorphous silicon

1997 ◽  
Author(s):  
S. Dong ◽  
J. Liebe ◽  
Y. Tang ◽  
R. Braunstein ◽  
B. von Roedern
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Potential Fluctuations ◽  
Hydrogenated Amorphous
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