High interfacial conductivity at amorphous silicon/crystalline silicon heterojunctions

Kleider, Jean‐Paul; Soro, Yrebegnan Moussa; Chouffot, Rémy; Gudovskikh, A. S.; Cabarrocas, Pere Roca i; Damon-Lacoste, J.; Eon, David; Ribeyron, P.J.

doi:10.1016/j.jnoncrysol.2007.09.087

Cited by 23 publications

(18 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12.23 for the current flow, the upper first path consisting in the flow within the a-Si:H layer is negligible. This has been verified experimentally by comparing the current measured in the a-Si:H/c-Si structure with that measured in the a-Si:H/glass structure [66,67]. An example is shown in Fig.…”

Section: Planar Conductance Techniquesupporting

confidence: 54%

Band Lineup Theories and the Determination of Band Offsets from Electrical Measurements

Kleider

2012

Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells

View full text Add to dashboard Cite

Abstract. Semiconductor heterojunctions have been used in the last decades to build devices with enhanced electrical or optoelectrical properties compared to those of equivalent homojunction devices. Examples of heterojunction devices are encountered in laser applications using band gap engineering possibilities in crystalline III-V compounds, and in bipolar transistors in crystalline silicon based electronics. More recently, heterojunctions formed between hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si) were introduced for the fabrication of silicon solar cells. The main advantage of heterojunctions over homojunctions is due to the band offsets that can provide selective barriers for one type of carriers. The determination of band offsets and band lineup at the interface is thus of crucial importance. A lot of theoretical work has been devoted to this issue. In parallel, various characterization techniques have been developed to provide experimental insight into band offsets. In this chapter the principal models for band lineup at interfaces are recalled, with particular emphasis on Anderson's electron affinity rule and Tersoff's branch-point energy alignment theory. The application to the a-Si:H/c-Si system is discussed. Then, the principal electrical characterization tools based on capacitance and admittance measurements are presented. After a general overview of the widely used capacitance versus bias voltage technique (so-called C-V or 1/C 2 method), the main potential problems and sources of uncertainty when applying this technique to the a-Si:H/c-Si system are addressed. Some features specific to the a-Si:H/c-Si interface are identified and illustrated using both numerical simulations and experimental data. These features are related to the amorphous nature of a-Si:H, e.g. the high density of band gap states, and to the existence of a strong inversion regime at the c-Si surface that can lead to two dimensional electron or hole gases. A simple technique based on the measurement of the planar conductance of a-Si:H/c-Si structures is presented. The determination of band offsets from such measurements and related modelling on both (p) a-Si:H / (n) c-Si and (n) a-Si:H / (p) c-Si structures is discussed. For interfaces used in high efficiency solar cells the band offsets are found to be 0.15 eV for the conduction band and 0.40 eV for the valence band.

show abstract

Section: Planar Conductance Techniquesupporting

confidence: 54%

Band Lineup Theories and the Determination of Band Offsets from Electrical Measurements

Kleider

2012

Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells

View full text Add to dashboard Cite

show abstract

“…Recently, there has been experimental confirmation of the existence of the inversion layer using capacitive methods, 9,10 planar conductivity measurements, [11][12][13] and conductive probe atomic force microscopy. 14,15 Until now, the inversion layer has been considered only as a tool to characterize the band offsets at the a-Si:H/c-Si interface 16,17 and its influence on lateral transport in operating devices has not yet been analyzed.…”

Section: Introductionmentioning

confidence: 99%

Analysis of lateral transport through the inversion layer in amorphous silicon/crystalline silicon heterojunction solar cells

Filipič

Holman

Smole

et al. 2013

Journal of Applied Physics

View full text Add to dashboard Cite

In amorphous/crystalline silicon heterojunction solar cells, an inversion layer is present at the front interface. By combining numerical simulations and experiments, we examine the contribution of the inversion layer to lateral transport and assess whether this layer can be exploited to replace the front transparent conductive oxide (TCO) in devices. For this, heterojunction solar cells of different areas (2 Â 2, 4 Â 4, and 6 Â 6 mm 2 ) with and without TCO layers on the front side were prepared. Laser-beam-induced current measurements are compared with simulation results from the ASPIN2 semiconductor simulator. Current collection is constant across millimeter distances for cells with TCO; however, carriers traveling more than a few hundred microns in cells without TCO recombine before they can be collected. Simulations show that increasing the valence band offset increases the concentration of holes under the surface of n-type crystalline silicon, which increases the conductivity of the inversion layer. Unfortunately, this also impedes transport across the barrier to the emitter. We conclude that the lateral conductivity of the inversion layer may not suffice to fully replace the front TCO in heterojunction devices. V C 2013 AIP Publishing LLC.

show abstract

“…The method is based on the existence of a strongly inverted layer in the crystalline material at the interface if a highly doped (n) a-Si:H layer is deposited on a (p) c-Si substrate [5,6], or for the inverted structure [7]. This forms a conductive channel that strongly depends on the band bending and thus on the band offsets.…”

Section: Introductionmentioning

confidence: 99%

Influence of the amorphous/crystalline silicon heterostructure properties on planar conductance measurements

Varache

Favre

Korte

et al. 2012

Journal of Non-Crystalline Solids

Self Cite

View full text Add to dashboard Cite

High interfacial conductivity at amorphous silicon/crystalline silicon heterojunctions

Cited by 23 publications

References 6 publications

Band Lineup Theories and the Determination of Band Offsets from Electrical Measurements

Band Lineup Theories and the Determination of Band Offsets from Electrical Measurements

Analysis of lateral transport through the inversion layer in amorphous silicon/crystalline silicon heterojunction solar cells

Influence of the amorphous/crystalline silicon heterostructure properties on planar conductance measurements

Contact Info

Product

Resources

About