Changes in surface topography of amorphous silicon germanium films after light soaking

Agarwal, Pramod; Srivastava, Alok; Deva, Dinesh

doi:10.1063/1.2721944

Cited by 11 publications

(15 citation statements)

References 25 publications

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“…8a) shows that during the first 40 min of light-soaking there is a strong decrease in the amplitude of ε 2 , which can be accounted by an increase of the surface roughness of the films (see Fig. 8e), consistent with published results [44] and AFM images (Figs. 4 and 5).…”

Section: Hydrogen Exodiffusion Studiessupporting

confidence: 80%

Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

et al. 2012

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We report on light-induced electrical and macroscopic changes in hydrogenated polymorphous silicon (pm-Si:H) PIN solar cells. To explain the particular light-soaking behavior of such cells -namely an increase of the open circuit voltage (Voc) and a rapid drop of the short circuit current density (Jsc) -we correlate these effects to changes in hydrogen incorporation and structural properties in the layers of the cells. Numerous techniques such as current-voltage characteristics, infrared spectroscopy, hydrogen exodiffusion, Raman spectroscopy, atomic force microscopy, scanning electron microscopy and spectroscopic ellipsometry are used to study the light-induced changes from microscopic to macroscopic scales (up to tens of microns). Such comprehensive use of complementary techniques lead us to suggest that light-soaking produces the diffusion of molecular hydrogen, hydrogen accumulation at p-layer/substrate interface and localized delamination of the interface. Based on these results we propose that light-induced degradation of PIN solar cells has to be addressed from not only as a material issue, but also a device point of view. In particular we bring experimental evidence that localized delamination at the interface between the p-layer and SnO2 substrate by light-induced hydrogen motion causes the rapid drop of Jsc.

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Section: Hydrogen Exodiffusion Studiessupporting

confidence: 80%

Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

et al. 2012

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“…In a-Si [16] and a-SiGe [13] the distribution of H is not uniform which causes local band gap variations, so-called elastic fluctuations of the band gap, the zones of less H content having the smaller band gap [13,16]. Voids where H has been released from Si (or Ge) atoms can be in our samples preferential sites where band gap fluctuations occur.…”

Section: Resultsmentioning

confidence: 94%

“…Based on the findings in the literature cited so far [1, and references therein] [3,5,[13][14][15][16] and on our recent ones [20] structural modifications have also to be expected in Si/Ge amorphous MLs made of ultrathin layers. By using atomic force microscopy (AFM) and transmission electron microscopy (TEM) this work will show that this is really the case.…”

Section: Introductionmentioning

confidence: 92%

AFM and TEM study of hydrogenated sputtered Si/Ge multilayers

Frigeri¹,

Nasi²,

Serényi

et al. 2009

Superlattices and Microstructures

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Multilayers of hydrogenated ultrathin (3 nm) amorphous a-Si and a-Ge layers prepared by sputtering have been studied by atomic force microscopy (AFM) and transmission electron microscopy (TEM) to check the influence of annealing on their structural stability. The annealed multilayers exhibit surface and bulk degradation with formation of bumps and craters whose density and size increase with increasing hydrogen content and/or annealing temperature and time. Bumps are due to the formation of H2 bubbles in the multilayer. The craters are bumps blown up very likely because of too high a gas pressure inside. The release of H from its bonds to Si and Ge occurs within cavities very likely present in the samples. The necessary energy is supplied by the heat treatment and by the recombination of thermally generated carriers. Results by energy filtered TEM on the interdiffusion of Si and Ge upon annealing are also presented

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“…If the voids are interconnected the a-Si:H very likely is not of the expected device grade quality since loss of H, by out-diffusion of atomic or molecular hydrogen, and possible in-diffusion of water and ambient molecules may occur depending on the void size (Beyer et al, 2012). Furthermore, the accumulation of the polyhydrides in (micro-)voids determines an inhomogeneous distribution of H that causes elastic potential fluctuations in the amorphous network resulting in a local variation in energy band gap (Agarwal et al, 2007). In particular, an increase of the optical band gap with increasing concentration of SiH 2 was observed (Manfredotti et al, 1994).…”

Section: Resultsmentioning

confidence: 97%

Effect of heat treatments on the properties of hydrogenated amorphous silicon for PV and PVT applications

Frigeri¹,

Serényi

Szekrényes

et al. 2015

Solar Energy

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Changes in surface topography of amorphous silicon germanium films after light soaking

Cited by 11 publications

References 25 publications

Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

AFM and TEM study of hydrogenated sputtered Si/Ge multilayers

Effect of heat treatments on the properties of hydrogenated amorphous silicon for PV and PVT applications

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