The Staebler-Wronski Effect: New Physical Approaches and Insights as a Route to Reveal its Origin

2010 ◽  
Vol 1245 ◽  
Author(s):  
Arno H.M. Smets ◽  
Chris R. Wronski ◽  
Miro Zeman ◽  
M. van de Sanden
Keyword(s):  
Experimental Evidence ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Defect States ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous ◽  
Metastable Defect ◽  
Hydrogen Bonded

AbstractIn the recent years more and more theoretical and experimental evidence have been found that the hydrogen bonded to silicon in dense hydrogenated amorphous silicon (a-Si:H) predominantly resides in hydrogenated divacancies. In this contribution we will philosophize about the option that the small fraction of divacancies, missing at least one of its bonded hydrogen, may correspond to some of the native and metastable defect states of a-Si:H. We will discuss that such defect entities are an interesting basis for new and alternative views on the origin of the SWE.

Characterization of the Bulk Recombination in Hydrogenated Amorphous Silicon Solar Cells

2004 ◽  
Vol 808 ◽  
Author(s):  
J. Deng ◽  
J.M. Pearce ◽  
V. Vlahos ◽  
R.W. Collins ◽  
C.R. Wronski
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Forward Bias ◽  
Hydrogenated Amorphous Silicon ◽  
Quality Factors ◽  
Defect States ◽  
Cell Structures ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous

ABSTRACTDark forward bias current, JD-V, characteristics offer a probe for characterizing carrier recombination and the defect states in the intrinsic layers of hydrogenated amorphous silicon (a-Si:H) solar cells. Detailed studies were carried out on such characteristics for the cells with optimized p/i interfaces and high quality i-layers in which the current transport is bulk recombination dominated. It was found that the diode quality factor n is not a constant with bias voltages as has been generally considered. Instead, it can be best described through the bias dependent differential diode quality factors, n(V) = [kT/q]−1[d(lnJD)/dV]−1, whose magnitude and shape reflect the gap state distribution in the corresponding bulk i-layers. The n(V) characteristics obtained on cell structures with both hydrogen diluted and undiluted i-layers have been utilized in characterizing the differences in the distribution of defect states in the two i-layers both in annealed state as well as after creating light induced defects. In the characterization of the Staebler-Wronski Effect (SWE) using JD-V characteristics, a newphenomenon is observed – relaxation of light induced defect states created by 1 sun illumination at 25°C, which is also found in the follow-on studies on the photo-conductivities of corresponding thin films.

Improved Light Soaking Stability of R.F. Sputter Deposited Amorphous Silicon

1991 ◽  
Vol 219 ◽  
Author(s):  
A. Wynveen ◽  
J. Fan ◽  
J. Kakalios ◽  
J. Shinar
Keyword(s):  
Amorphous Silicon ◽  
Hydrogen Content ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Dark Conductivity ◽  
Initial Defect ◽  
Optical Gap ◽  
Sputter Deposited ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous

ABSTRACTStudies of r.f. sputter deposited hydrogenated amorphous silicon (a-Si:H) find that the light induced decrease in the dark conductivity and photoconductivity (the Staebler-Wronski effect) is reduced when the r.f. power used during deposition is increased. The slower Staebler-Wronski effect is not due to an increase in the initial defect density in the high r.f. power samples, but may result from either the lower hydrogen content or the smaller optical gap found in these films.

Theoretical Studies of Structure and Doping of Hydrogenated Amorphous Silicon

2011 ◽  
Vol 1321 ◽  
Author(s):  
Bin Cai ◽  
D. A. Drabold
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Theoretical Studies ◽  
Defect States ◽  
High Impurity ◽  
Bond Center ◽  
B Doping ◽  
Hydrogenated Amorphous ◽  
Center Site

ABSTRACTIn a-Si:H, large concentrations of B or P (of order 1%) are required to dope the material, suggesting that doping mechanisms are very different than for the crystal for which much smaller concentrations are required. In this paper, we report simulations on B and P introduced into realistic models of a-Si:H and a-Si, with concentrations ranging from 1.6% to 12.5% of B or P in the amorphous host. The results indicate that tetrahedral B and P are effective doping configurations in a-Si, but high impurity concentrations introduce many defect states. For a-Si:H, we report that both B(3,1) and P(3,1) (B or P atom bonded with three Si atoms and one H atom) are effective doping configurations. We investigate H passivation in both cases. For both B and P, there exists a “hydrogen poison range” of order 6 Å for which H in a bond-center site can suppress doping. For B doping, nearby H prefers to stay at the bond-center of Si-Si, leaves B four-fold and neutralizes the doping configuration; for P doping, nearby H spoils the doping by inducing a reconstruction rendering initially tetrahedral P three-fold.

Defect States in Hydrogenated Amorphous Silicon-Sulphur Alloys by ESR and PAS

1991 ◽  
Vol 219 ◽  
Author(s):  
Gaorong Han ◽  
Jianmin Qiao ◽  
Piyi Du ◽  
Zhonghua Jiang ◽  
Zishang Ding
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Spin Density ◽  
Molecular Hydrogen ◽  
Annealing Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Sulphur Content ◽  
Defect States ◽  
Hydrogenated Amorphous

ABSTRACTWe have presented ESR and PAS measurements for a series of a-SiS:H and a-Si: H films deposited by glow discharge at different parameters. The spin density in a-SiS:H alloys measured by ESR is essentially independent of the sulphur content, while the density of defects measured by PAS increases significantly with the increasing of sulphur content. The ESR signals in a-SiS:H alloys strongly depend on both annealing and illumination. The spin density increases up to 540°C and then decreases with raising annealing temperature for a-SiS:H and a-Si:H alloys. The results suggest that some new defects such as molecular hydrogen and microvoids are appeared when addition of sulphur to a-Si:H films.

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