Microscopic study of the H2O vapor treatment of the silicon grain boundaries

Honda, Shinya; Mates, T.; Rezek, Bohuslav; Fejfar, A.; Kočka, J.

doi:10.1016/j.jnoncrysol.2007.09.107

Cited by 13 publications

(9 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Kelvin probe force microscopy (KFM) is considered one of the most powerful methods for evaluating potential variations in the GB characteristics. For polycrystalline Si and compound semiconductors, the GBs characteristics have been discussed in detail in terms of GB band lineup and barrier height using KFM[85][86][87][88]. In this study, we analyzed the potential variations and barrier heights around GBs in BaSi2 epitaxial films both on Si(111) and Si(001) substrates using KFM in air.Figs.…”

mentioning

confidence: 99%

Exploring the potential of semiconducting BaSi₂for thin-film solar cell applications

Suemasu

Usami

2016

J. Phys. D: Appl. Phys.

114

106

View full text Add to dashboard Cite

Semiconducting barium disilicide (BaSi2), which is composed of earth-abundant elements, has attractive features for thin-film solar cell applications; both a large absorption coefficient comparable to copper indium gallium diselenide and a minority-carrier diffusion length much larger than the grain size of BaSi2 can be used to improve solar cells properties. In this review article, we explore the potential of semiconducting BaSi2 films for thin-film solar cell applications. We start by describing its crystal and energy band structure, followed by discussing thin-film growth techniques and the optical and electrical properties of BaSi2 films. We used a first-principle calculation based on density-functional theory to calculate the position of the Fermi level to predict the carrier type of impurity-doped BaSi2 films using either a Group 13 or 15 element, and compare the calculated results with the experimental ones. Special attention was paid to the minority-carrier properties, such as minority-carrier lifetime, minority-carrier diffusion length, and surface passivation. The potential variations across the grain boundaries measured by Kelvin-probe force microscopy allowed us to detect a larger minority-carrier diffusion length in BaSi2 on Si(111) compared with in BaSi2 on Si(001). Finally, we demonstrate the operation of p-BaSi2/n-Si heterojunction solar cells and discuss prospects for future development.

show abstract

mentioning

confidence: 99%

Exploring the potential of semiconducting BaSi₂for thin-film solar cell applications

Suemasu

Usami

2016

J. Phys. D: Appl. Phys.

114

106

View full text Add to dashboard Cite

show abstract

“…For polycrystalline Si and compound semiconductors, GBs character was discussed in detail from the view points of band lineup and barrier height around the GBs using KFM. [19][20][21][22] In this study, we analyzed potential variations and barrier heights around the GBs in BaSi 2 epitaxial films both on Si(111) and Si(001) substrates using KFM.…”

mentioning

confidence: 99%

Evaluation of potential variations around grain boundaries in BaSi2 epitaxial films by Kelvin probe force microscopy

Baba

Tsurekawa

Watanabe

et al. 2013

Applied Physics Letters

View full text Add to dashboard Cite

Potential variations around the grain boundaries (GBs) on the surface in undoped n-BaSi 2 epitaxial films on Si(111) and Si(001) were analyzed using Kelvin prove force microcopy. The potentials were higher at GBs than those in the BaSi 2 grains on Si(111). The average barrier height was approximately 30 meV at the GBs, indicating that the enhanced potentials repulse photogenerated holes so that the charge carrier recombination can be effectively reduced. In contrast, the potentials were smaller at GBs in the BaSi 2 on Si (001), and the average barrier heights were approximately 30 and 50 meV along Si[1-10] and [110], respectively. V C 2013 AIP Publishing LLC. [http://dx.

show abstract

“…Contrary to this, if the steam pressure is too high, there is an undesirably high concentration of the passivating particles that can shift chemical equilibrium of a particular subreaction of the passivation process and prevent further saturation of defects. Another explanation can be that hydrogen introduced new structural defects into silicon as already presented in some previous studies [15,27].…”

Section: 2mentioning

confidence: 75%

“…Passivating species can be for instance hydrogen radicals produced by the commonly used plasma hydrogenation process [13]. Nevertheless, water vapour has a similar passivation potential according to the previous investigations [14,15] and lower processing costs make it very attractive.…”

mentioning

confidence: 99%

Passivation effect of water vapour on thin film polycrystalline Si solar cells

Pikna

Müller

Becker

et al. 2016

Physica Status Solidi (a)

View full text Add to dashboard Cite

In this work, we investigated a passivation of both surface and bulk of polycrystalline silicon films by water vapour. To assess the passivation effect we used Suns‐VOC method to measure the open‐circuit voltage VOC of polycrystalline silicon thin film solar cells. The treatment conditions, i.e. temperature, steam pressure, duration, were systematically varied to optimise the passivation process. According to our results, there is a parameter interaction because the same passivation effect can be achieved at different treatment conditions. A sufficiently high temperature (350–450 °C) is necessary for a successful silicon passivation. The impact of this parameter cannot be replaced either by an elevated steam pressure or a prolonged exposure time. Nevertheless, the passivation effect of steam can be strengthened by an elevated steam pressure. Different gases were tested beside water vapour, e.g. H2, H2 + H2O, O2 + H2O, air, but none of them resulted in higher VOC than pure steam (360 mV from starting 220 mV). Results from Fourier transform infrared spectroscopy indicate that water vapour passivation is rather oxidation while hydrogen plays a significant supporting role in the process. We conclude that the water vapour passivation is able to passivate defects in the whole silicon volume. However, its passivation effect is not strong enough to become an adequate alternative to the plasma hydrogenation with the best result of VOC ∼497 mV. On the other hand, it provides advantage of simplicity (no vacuum system and deionised water steam as the only input). Recombination activity of defects in polycrystalline Si can be suppressed by their saturation for instance in hydrogen plasma (Si–H) or in water vapour (Si–O–Si).

show abstract

Microscopic study of the H2O vapor treatment of the silicon grain boundaries

Cited by 13 publications

References 9 publications

Exploring the potential of semiconducting BaSi₂for thin-film solar cell applications

Exploring the potential of semiconducting BaSi₂for thin-film solar cell applications

Evaluation of potential variations around grain boundaries in BaSi2 epitaxial films by Kelvin probe force microscopy

Passivation effect of water vapour on thin film polycrystalline Si solar cells

Contact Info

Product

Resources

About

Microscopic study of the H2O vapor treatment of the silicon grain boundaries

Cited by 13 publications

References 9 publications

Exploring the potential of semiconducting BaSi2for thin-film solar cell applications

Exploring the potential of semiconducting BaSi2for thin-film solar cell applications

Evaluation of potential variations around grain boundaries in BaSi2 epitaxial films by Kelvin probe force microscopy

Passivation effect of water vapour on thin film polycrystalline Si solar cells

Contact Info

Product

Resources

About

Exploring the potential of semiconducting BaSi₂for thin-film solar cell applications

Exploring the potential of semiconducting BaSi₂for thin-film solar cell applications