Determination of band offsets in a-Si:H/c-Si heterojunctions from capacitance–voltage measurements: Capabilities and limits

Gudovskikh, A. S.; Ibrahim, Siti Zuraidah; Kleider, Jean‐Paul; Damon-Lacoste, J.; Cabarrocas, Pere Roca i; Veschetti, Y.; Ribeyron, P.J.

doi:10.1016/j.tsf.2006.11.198

Cited by 40 publications

(25 citation statements)

References 9 publications

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“…This leads to the conclusion that the high conductance of the c-Si samples comes from the interface. Indeed, due to the band mismatch between c-Si and a-Si:H, an electron rich inversion layer can exist in c-Si at the interface, as already suggested from capacitance versus voltage measurements [5]. When the a-Si:H layer is etched the inversion layer also disappears so that both G a-Si:H and G int are suppressed, and the equivalent circuit (Fig.…”

Section: Discussionmentioning

confidence: 65%

High interfacial conductivity at amorphous silicon/crystalline silicon heterojunctions

Kleider

Soro

Chouffot

et al. 2008

Journal of Non-Crystalline Solids

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Section: Discussionmentioning

confidence: 65%

High interfacial conductivity at amorphous silicon/crystalline silicon heterojunctions

Kleider

Soro

Chouffot

et al. 2008

Journal of Non-Crystalline Solids

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“…As was shown by Gudovskikh et al [4], due to the presence of the inversion layer on the a-Si:H(n)/c-Si(p) heterostructure, it is not possible to determine the diffusion voltage from the C −V measurement of such structure. Therefore, we carried out the simulation study using the ASA program to confirm or reject the presence of inversion layer in the studied samples.…”

Section: Capacitance-voltage Measurementsmentioning

confidence: 99%

Capacitance Analysis of the Structures with the a-Si:H(i)/c-Si(p) Heterojunction for Solar-Cell Applications

Mikolášek

Jakaboviš

Řeháček

et al. 2014

Journal of Electrical Engineering

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In this paper we present the capacitance study of the intrinsic amorphous silicon/crystalline silicon heterostructure with the aim to gain insight on the heterointerface properties of a passivated silicon heterojunction solar cell. It is shown that due to the high density of defect states in the amorphous layer the structure has to be analyzed as a heterojunction. Using the analysis, the following values have been determined: conduction-band offset of 0.13 eV, electron affinity of 3.92 eV, and density of defect states in the intrinsic amorphous silicon being that of 4.14 X 1021m—3.

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“…In the same way, the method applied to (n) a-Si:H / (p) c-Si structure leads to underestimated values for ΔE C . For the latter N/p structure, a critical study of the C-V intercept method has been performed [63]. By changing the conduction band offset value in the calculations (all other parameters being constant) it has been shown that there are two reasons that explain the underestimated values obtained for the band offset.…”

Section: Application To the A-si:h/c-si Systemmentioning

confidence: 99%

“…The intercept voltage of the C-V method reflects the potential drop of the depleted region in the c-Si layer, and does not account for the two additional potential drops in a-Si:H and in the strong inversion layer in c-Si. This is why, when increasing the band offset the intercept voltage of the C-V method saturates at a value close to the potential drop in the depleted region of c-Si and does not increase linearly as does V d [63]. So far, the theoretical considerations and calculations did not take account of interface states that do exist at the a-Si:H/c-Si interface.…”

Section: Application To the A-si:h/c-si Systemmentioning

confidence: 99%

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

Kleider

2012

Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells

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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.

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Determination of band offsets in a-Si:H/c-Si heterojunctions from capacitance–voltage measurements: Capabilities and limits

Cited by 40 publications

References 9 publications

High interfacial conductivity at amorphous silicon/crystalline silicon heterojunctions

High interfacial conductivity at amorphous silicon/crystalline silicon heterojunctions

Capacitance Analysis of the Structures with the a-Si:H(i)/c-Si(p) Heterojunction for Solar-Cell Applications

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

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