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Characterization of silicon heterojunctions for solar cells.

Kleider JP, Alvarez J, Ankudinov AV, Gudovskikh AS, Gushchina EV, Labrune M, Maslova OA, Favre W, Gueunier-Farret ME, Roca I Cabarrocas P, Terukov EI - Nanoscale Res Lett (2011)

Bottom Line: This is in good agreement with planar conductance measurements that show a large interface conductance.It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions.These are intimately related to the band offsets, which allows us to determine these parameters with good precision.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Génie Electrique de Paris, CNRS UMR 8507, SUPELEC, Univ P-Sud, UPMC Univ Paris 6, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette Cedex, France. jean-paul.kleider@lgep.supelec.fr.

ABSTRACT
Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that show a large interface conductance. It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions. These are intimately related to the band offsets, which allows us to determine these parameters with good precision.

No MeSH data available.


Sketch of the samples prepared for (a) CP-AFM measurements and (b) planar conductance measurements.
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Figure 3: Sketch of the samples prepared for (a) CP-AFM measurements and (b) planar conductance measurements.

Mentions: For these CP-AFM measurements, the normal solar cell structure was replaced by a simpler symmetric configuration, see Figure 3a, where the same a-Si:H layer was deposited on both sides of the c-Si wafer. Then ITO electrodes were deposited on top of both sides of the wafer, before the sample was cleaved. Some tests were also performed with aluminum instead of ITO as electrodes. The obtained CP-AFM results were globally the same. However, aluminum electrodes formed high ridges at the cleaved edge and their cross-section were poorly conductive due to strong oxidation of aluminum, what induced some problems in AFM imaging. Therefore, here we focus on samples with ITO on both sides. Thus, cleaved sections of ITO/(n) a-Si:H/(p) c-Si/ITO and ITO/(p) a-Si:H/(n) c-Si/ITO samples with different thicknesses of the a-Si:H layer (20, 100, 300 nm) were investigated.


Characterization of silicon heterojunctions for solar cells.

Kleider JP, Alvarez J, Ankudinov AV, Gudovskikh AS, Gushchina EV, Labrune M, Maslova OA, Favre W, Gueunier-Farret ME, Roca I Cabarrocas P, Terukov EI - Nanoscale Res Lett (2011)

Sketch of the samples prepared for (a) CP-AFM measurements and (b) planar conductance measurements.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211203&req=5

Figure 3: Sketch of the samples prepared for (a) CP-AFM measurements and (b) planar conductance measurements.
Mentions: For these CP-AFM measurements, the normal solar cell structure was replaced by a simpler symmetric configuration, see Figure 3a, where the same a-Si:H layer was deposited on both sides of the c-Si wafer. Then ITO electrodes were deposited on top of both sides of the wafer, before the sample was cleaved. Some tests were also performed with aluminum instead of ITO as electrodes. The obtained CP-AFM results were globally the same. However, aluminum electrodes formed high ridges at the cleaved edge and their cross-section were poorly conductive due to strong oxidation of aluminum, what induced some problems in AFM imaging. Therefore, here we focus on samples with ITO on both sides. Thus, cleaved sections of ITO/(n) a-Si:H/(p) c-Si/ITO and ITO/(p) a-Si:H/(n) c-Si/ITO samples with different thicknesses of the a-Si:H layer (20, 100, 300 nm) were investigated.

Bottom Line: This is in good agreement with planar conductance measurements that show a large interface conductance.It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions.These are intimately related to the band offsets, which allows us to determine these parameters with good precision.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Génie Electrique de Paris, CNRS UMR 8507, SUPELEC, Univ P-Sud, UPMC Univ Paris 6, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette Cedex, France. jean-paul.kleider@lgep.supelec.fr.

ABSTRACT
Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that show a large interface conductance. It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions. These are intimately related to the band offsets, which allows us to determine these parameters with good precision.

No MeSH data available.