Transparent Conducting Oxides Based on Tin Oxide

Kykyneshi, Robert; Jian-ping, Zeng; Cann, David P.

doi:10.1007/978-1-4419-1638-9_6

Cited by 18 publications

(13 citation statements)

References 85 publications

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“…The results for the SnO 2 :F layer of the TEC™ 15 in the solar cell yield a sheet resistance of 11.5 ± 1.1 Ω/sq, as determined from the resistivity and thickness and indicated in Table , which includes the key best fit optical parameters. Also from the resistivity and scattering time, a carrier concentration of 5.43 × 10 20 cm −3 and a mobility of 50 cm 2 /V s are deduced, assuming an electron effective mass for SnO 2 :F of m e * = 0.25 m e . In addition to the SnO 2 :F Drude parameters, whose best fit values are provided in Table , the constant contribution to the real part of ε ( E ) is varied for both the SnO 2 :F and the HRT layers.…”

Section: Resultsmentioning

confidence: 99%

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Koirala

Yoon

et al. 2016

Prog. Photovolt: Res. Appl.

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Polycrystalline CdS/CdTe thin-film solar cells in the superstrate configuration have been studied by spectroscopic ellipsometry (SE) using glass side illumination. In this measurement method, the first reflection from the ambient/glass interface is rejected, whereas the second reflection from the glass/film-stack interface is collected; higher order reflections are also rejected. The SE analysis incorporates parameterized dielectric functions ε for solar cell component materials obtained by in situ and variableangle SE. In the SE analysis of the complete cells, a step-wise procedure ranks the fitting parameters, including thicknesses and those defining the spectra in ε, according to their ability to reduce the root-mean-square deviation between the simulated and measured SE spectra. The best fit thicknesses from this analysis are found to be consistent with electron microscopy. Based on the SE results, the solar cell quantum efficiency (QE) can be simulated without any free parameters, and comparisons with measured QE enable optical model refinements as well as identification of optical and electronic losses. These capabilities have wide applications in photovoltaic module mapping and in-line monitoring.

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Section: Resultsmentioning

confidence: 99%

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Koirala

Yoon

et al. 2016

Prog. Photovolt: Res. Appl.

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“…ZnO is also more reactive towards oxygen than In 2 O 3 and therefore requires a more strict control of the oxygen supply during deposition [97]. F doped SnO 2 (FTO) offers exceptional chemical stability, high hardness, and excellent thermal stability although the minimum resistivity of 5 × 10 −4 Ω cm is higher than the best values achieved for ZnO:Al and ITO (10 −4 Ω cm) [98].…”

Section: Transparent Back Contactsmentioning

confidence: 99%

Back and front contacts in kesterite solar cells: state-of-the-art and open questions

et al. 2019

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We review the present state-of-the-art within back and front contacts in kesterite thin film solar cells, as well as the current challenges. At the back contact, molybdenum (Mo) is generally used, and thick Mo(S, Se) 2 films of up to several hundred nanometers are seen in record devices, in particular for selenium-rich kesterite. The electrical properties of Mo(S, Se) 2 can vary strongly depending on orientation and indiffusion of elements from the device stack, and there are indications that the back contact properties are less ideal in the sulfide as compared to the selenide case. However, the electronic interface structure of this contact is generally not well-studied and thus poorly understood, and more measurements are needed for a conclusive statement. Transparent back contacts is a relatively new topic attracting attention as crucial component in bifacial and multijunction solar cells. Front illuminated efficiencies of up to 6% have so far been achieved by adding interlayers that are not always fully transparent. For the front contact, a favorable energy level alignment at the kesterite/CdS interface can be confirmed for kesterite absorbers with an intermediate [S]/([S]+[Se]) composition. This agrees with the fact that kesterite absorbers of this composition reach highest efficiencies when CdS buffer layers are employed, while alternative buffer materials with larger band gap, such as Cd 1−x Zn x S or Zn 1−x Sn x O y , result in higher efficiencies than devices with CdS buffers when sulfurrich kesterite absorbers are used. Etching of the kesterite absorber surface, and annealing in air or inert atmosphere before or after buffer layer deposition, has shown strong impact on device performance. Heterojunction annealing to promote interdiffusion was used for the highest performing sulfide kesterite device and air-annealing was reported important for selenium-rich record solar cells. Cu 2 ZnSnS 4 (CZTS) absorbers for solar cell applications was first reported by Ito and Nakazawa [1]. Early results on CZTS device performance were reported by Friedlmeier et al [2], Seol et al [3], and Katagiri et al [4]. Later a group at IBM reached record performances with power conversion efficiencies (PCEs) above 10% for CZTSSe devices in 2010 [5] and the current record PCE of 12.6% in 2013 [6]. In 2018, researchers from DGIST reached the same performance, 12.6%, but for a larger device area [7]. The device structure used for kesterite solar cells was originally copied from that of Cu(In, Ga)Se 2 , (CIGSe) TFSCs, and is formed by sequential deposition, upon a soda lime glass substrate, of a Mo back contact, the absorber, a CdS buffer layer, and a ZnO/ZnO:Al bi-layer window (i.e. transparent top contact). This structure, schematically shown for CZTSSe in figure 1, is not necessarily ideal for kesterite solar cells, and extensive work has been invested into studies of alternative backand front contacts and related deposition processes. In this paper, the state-of-the-art and current open questions related to the back and front c...

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“…This widening of optical band gap is generally attributed to the Burstein-Moss shift (Kykyneshi et al 2010), which results from the filling of electronic states near the bottom of the conduction band, due to the increase of carrier concentration in the ZnO film. In this process, the apparent band gap of a semiconductor is increased as the absorption edge is pushed to higher energies, because of all states close to the conduction band being populated.…”

Section: Resultsmentioning

confidence: 99%

“…The electron generation can be explained using Kroger-Vink notation according to Eq. (2) (Kykyneshi et al 2010).…”

Section: Resultsmentioning

confidence: 99%

Study of the doping of thermally evaporated zinc oxide thin films with indium and indium oxide

2012

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The present paper reports observations made on investigations carried out to study structural, optical and electrical properties of thermally evaporated ZnO thin films and their modulations on doping with metallic indium and indium oxide separately. ZnO thin film in the undoped state is found to have a very good conductivity of 90 X -1 cm -1 with an excellent transmittance of up to 90 % in the visible region. After doping with metallic indium, the conductivity of the film is found to be 580 X -1 cm -1 , whereas the conductivity of indium oxide-doped films is increased up to 3.5 9 10 3 X -1 cm -1 . Further, the optical band gap of the ZnO thin film is widened from 3.26 to 3.3 eV when doped with indium oxide and with metallic indium it decreases to 3.2 eV. There is no considerable change in the transmittance of the films after doping. All undoped and doped films were amorphous in nature with smooth and flat surface without significant modifications due to doping.

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Transparent Conducting Oxides Based on Tin Oxide

Cited by 18 publications

References 85 publications

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Back and front contacts in kesterite solar cells: state-of-the-art and open questions

Study of the doping of thermally evaporated zinc oxide thin films with indium and indium oxide

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