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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 CP-AFM measurements; left: setup at LGEP with the resiscope extension; right: detail of the sample configuration and biasing.
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Figure 2: Sketch of the CP-AFM measurements; left: setup at LGEP with the resiscope extension; right: detail of the sample configuration and biasing.

Mentions: CP-AFM measurements were carried out using two different setups (i) in Ioffe Physical-technical Institute (NT-MDT Ntegra Aura) and (ii) in Laboratoire de Génie Électrique de Paris (Digital Instruments Nanoscope IIIa Multimode AFM with the RESISCOPE extension [4]). These setups allow one to apply a stable DC bias voltage to the device and to measure the resulting current flowing through the tip as the sample surface is scanned in contact mode. Schematic AFM setup is shown in Figure 2. In both measurements diamond-coated conductive probes made of silicon were used, the contact interaction force being in the range 100-500 nN. With the help of this technique one can simultaneously examine on the sample cleavages the surface topography and conductive properties of the layers constituting the solar cells. Note that, due to different softwares, the first setup provides images with current values (current flowing through the tip), while the second one provides resistance values, the resistance being defined as the ratio of the applied voltage to the measured current.


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 CP-AFM measurements; left: setup at LGEP with the resiscope extension; right: detail of the sample configuration and biasing.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Sketch of the CP-AFM measurements; left: setup at LGEP with the resiscope extension; right: detail of the sample configuration and biasing.
Mentions: CP-AFM measurements were carried out using two different setups (i) in Ioffe Physical-technical Institute (NT-MDT Ntegra Aura) and (ii) in Laboratoire de Génie Électrique de Paris (Digital Instruments Nanoscope IIIa Multimode AFM with the RESISCOPE extension [4]). These setups allow one to apply a stable DC bias voltage to the device and to measure the resulting current flowing through the tip as the sample surface is scanned in contact mode. Schematic AFM setup is shown in Figure 2. In both measurements diamond-coated conductive probes made of silicon were used, the contact interaction force being in the range 100-500 nN. With the help of this technique one can simultaneously examine on the sample cleavages the surface topography and conductive properties of the layers constituting the solar cells. Note that, due to different softwares, the first setup provides images with current values (current flowing through the tip), while the second one provides resistance values, the resistance being defined as the ratio of the applied voltage to the measured current.

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.