Improved compositional flexibility of Cu(In,Ga)Se2-based thin film solar cells by sodium control technique

Nakada, Tokio; Ohbo, Hiroki; Fukuda, Masahiro; Kunioka, Akio

doi:10.1016/s0927-0248(97)00202-x

Cited by 44 publications

(23 citation statements)

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“…[103][104][105][106] A decreasing grain size was observed for several Na incorporation methods in a direct comparison. 107 The CIS compound formation in rapid-thermal-processed layers was found to be delayed in the presence of Na, resulting in CIS growth at a higher mean temperature, which serves as an explanation for the observed increase in grain size.…”

Section: Sodium Incorporation In Cigsmentioning

confidence: 99%

“…109 In several reports, 99,101 a change in texture of CIGS films towards (112) orientation has been attributed to Na and supported by theoretical considerations for the case of high Na concentrations, 110 but remains disputed, owing to contrary results. 100,104,106,107 Higher doses of Na are shown to lead to small grain sizes and porous films and to be detrimental to the cell performance. 104,105 The most obvious electronic effect of Na incorporation into CIGS films is a decrease in resistivity by up to two orders of magnitude.…”

Section: Sodium Incorporation In Cigsmentioning

confidence: 99%

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Development of thin‐film Cu(In,Ga)Se₂and CdTe solar cells

Romeo¹,

Terheggen²,

Abou‐Ras³

et al. 2004

Progress in Photovoltaics

358

192

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Cu(In,Ga)Se2 and CdTe heterojunction solar cells grown on rigid (glass) or flexible foil substrates require p‐type absorber layers of optimum optoelectronic properties and n‐type wide‐bandgap partner layers to form the p–n junction. Transparent conducting oxide and specific metal layers are used for front and back electrical contacts. Efficiencies of solar cells depend on various deposition methods as they control the optoelectronic properties of the layers and interfaces. Certain treatments, such as addition of Na in Cu(In,Ga)Se2 and CdCl2 treatment of CdTe have a direct influence on the electronic properties of the absorber layers and efficiency of solar cells. Processes for the development of superstrate and substrate solar cells are reviewed. Copyright © 2004 John Wiley & Sons, Ltd.

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Section: Sodium Incorporation In Cigsmentioning

confidence: 99%

Section: Sodium Incorporation In Cigsmentioning

confidence: 99%

Development of thin‐film Cu(In,Ga)Se₂and CdTe solar cells

Romeo¹,

Terheggen²,

Abou‐Ras³

et al. 2004

Progress in Photovoltaics

358

192

View full text Add to dashboard Cite

show abstract

“…20 Na incorporation has also been reported to be crucial in governing absorber morphology and grain growth, 21 although a quantified optimal amount of Na has yet to be found, with contradictory observations reported. [22][23][24] It has been proposed that Na mainly exists in CIGS as substitutional point defect at Cu and In vacancy sites and alter the dopant concentration and bandgap by introducing acceptor-type defect complex such as Na In . 25 Other reports show that Na has a strong preference for the charge-neutral Cu substitution and affects the electronic properties indirectly by means such as introducing new diffusion pathways.…”

mentioning

confidence: 99%

Strength, stiffness, and microstructure of Cu(In,Ga)Se2 thin films deposited via sputtering and co-evaporation

Luo

Lee

et al. 2014

Applied Physics Letters

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This work examines Cu(In,Ga)Se2 thin films fabricated by (1) selenization of pre-sputtered Cu-In-Ga and (2) co-evaporation of each constituent. The efficiency disparity between films deposited via these two methods is linked to differences in morphology and microstructure. Atomic force microscopy and scanning electron microscopy show that selenized films have rougher surfaces and poor adhesion to molybdenum back contact. Transmission electron microscopy and electron energy loss spectroscopy revealed multiple voids near the Mo layer in selenized films and a depletion of Na and Se around the voids. Residual stresses in co-evaporated films were found to be ∼1.23 GPa using wafer curvature measurements. Uniaxial compression experiments on 500 nm-diameter nanopillars carved out from co-evaporated films revealed the elastic modulus of 70.4 ± 6.5 GPa. Hertzian contact model applied to nanoindentation data on selenized films revealed the indentation modulus of 68.9 ± 12.4 GPa, which is in agreement with previous reports. This equivalence of the elastic moduli suggests that microstructural differences manifest themselves after the yield point. Typical plastic behavior with two distinct failure modes is observed in the extracted stress-strain results, with the yield strength of 640.9 ± 13.7 MPa for pillars that failed by shearing and 1100.8 ± 77.8 MPa for pillars that failed by shattering.

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“…An increased range of compositions (specifically, negative molecularity deviations) that yield devices with comparable performance [144][145][146].…”

Section: Alkali Impurities In Cis and Related Materialsmentioning

confidence: 99%

Processing of CuInSe2-Based Solar Cells: Characterization of Deposition Processes in Terms of Chemical Reaction Analyses. Final Report, 6 May 1995 - 31 December 1998

Anderson¹,

Stanbery²

2001

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This project was initiated after the Boeing Company decided to terminate its photovoltaic research and development efforts, and donated some research equipment to UF. Billy Stanbery, who was part of the Boeing team, decided then to enroll at UF to pursue a Ph.D degree. As such these events constituted a rare direct technology transfer from industry to a university. This helped to preserve more than the published legacy of the solar cell efforts at Boeing, and jump-started a comprehensive, multifaceted, and multidisciplinary copper indium diselenide solar cell research effort at UF. 5-15 Micro-Raman scattering spectra of islands on two indium-rich CIS films grown on GaAs (100). The uppermost curve is from an island "pool" on a sodium-dosed film and the lower two are single and averaged spectra from isolated islands on the sample without sodium shown in Figure 5- field. It focused primarily on the physical and opto-electronic properties of the general class of I-III-VI2 and II-IV-V2 compound semiconductors. More recent reviews specifically oriented towards CIS materials and electronic properties [2][3][4][5][6] are also recommended reading for those seeking to familiarize themselves with key research results in this field.There are also a number of excellent books and reviews on photovoltaic device physics [7,8], on the general subject of solar cells and their applications [9,10], and others specifically oriented towards thin-film solar cells [11,12] Researchers have not always been careful to reserve the use of the compound designation CuInSe2 for single-phase material of the designated stoichiometry, an imprecision that is understandable in view of the difficulty in discriminating CuInSe2 from some other compounds in this material system, as will be discussed in detail elsewhere in this treatise. The compound designations such as CuInSe2 will be reserved herein for reference to single-phase material of finite solid solution extent, and multiphasic or materials of indeterminate structure composed of copper, indium, and selenium will be referred to by the customary acronym, in this case CIS. 3 This review begins with an overview of the physical properties of the principal copper ternary chalcogenides utilized for PV devices, including their thermochemistry, crystallography, and opto-electronic properties. All state-ofthe-art devices rely on alloys of these ternary compounds and employ alkali impurities, so the physical properties and effects of these additives will be presented, with an emphasis on their relevance to electronic carrier transport properties. This foundation will provide a basis from which to address the additional complexities and variability resulting from the plethora of materials processing methods and device structures which have been successfully employed to fabricate high efficiency PV devices utilizing absorbers belonging to this class of materials. Phase Chemistry of Cu-III-VI Material SystemsSignificant technological applications exist for Ag-III-VI2 compounds as non-linear optical mat...

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Improved compositional flexibility of Cu(In,Ga)Se2-based thin film solar cells by sodium control technique

Cited by 44 publications

References 1 publication

Development of thin‐film Cu(In,Ga)Se₂and CdTe solar cells

Development of thin‐film Cu(In,Ga)Se₂and CdTe solar cells

Strength, stiffness, and microstructure of Cu(In,Ga)Se2 thin films deposited via sputtering and co-evaporation

Processing of CuInSe2-Based Solar Cells: Characterization of Deposition Processes in Terms of Chemical Reaction Analyses. Final Report, 6 May 1995 - 31 December 1998

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Improved compositional flexibility of Cu(In,Ga)Se2-based thin film solar cells by sodium control technique

Cited by 44 publications

References 1 publication

Development of thin‐film Cu(In,Ga)Se2and CdTe solar cells

Development of thin‐film Cu(In,Ga)Se2and CdTe solar cells

Strength, stiffness, and microstructure of Cu(In,Ga)Se2 thin films deposited via sputtering and co-evaporation

Processing of CuInSe2-Based Solar Cells: Characterization of Deposition Processes in Terms of Chemical Reaction Analyses. Final Report, 6 May 1995 - 31 December 1998

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Development of thin‐film Cu(In,Ga)Se₂and CdTe solar cells

Development of thin‐film Cu(In,Ga)Se₂and CdTe solar cells