The effect of NaF on Cu(In,Ga)Se2 thin film solar cells

Granath, Karin; Bodegård, Marika; Stolt, Lars

doi:10.1016/s0927-0248(99)00089-6

Cited by 184 publications

(105 citation statements)

References 3 publications

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“…As sodium does not diffuse through FTO, a NaF layer is deposited onto the transparent back contact prior to the CGS deposition process using physical vapor deposition. It is necessary to supply sodium as it plays a crucial role for high quality absorbers [7].…”

Section: Methodsmentioning

confidence: 99%

Effect of Cu excess on three-stage CuGaSe2 thin films using in-situ process controls

Caballero¹,

Siebentritt²,

Sakurai³

et al. 2007

Thin Solid Films

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The objective of this work is to study the effect of Cu-excess and compare the growth mechanism of CuGaSe 2 (CGS) films coevaporated using a bilayer and a three-stage process and evaluate the consequences of the latter for CGS on transparent back contacts. CGS thin films are prepared by coevaporation in a three-stage process onto Mo/soda-lime substrates and onto FTO. In contrast to the bilayer process, Cu-Se phases are only observed on the surface at the end of the second stage, e 2 . This allows to work with a broader Cu-excess window. Atomic ratios (Cu/Ga)e 2 of around 1.3 at the end of deposition phase 2 in the three-stage process show the better device efficiencies due to a larger grain formation. Increasing the Cu-content leads to a slight decrease of the grain size and voids are observed in the film, reducing the FF of the device. The CGS morphology and the solar cells efficiency are dominated by the Cu excess more than by the T substrate between 535° C and 500° C. Similar results are obtained for CGS on FTO: (Cu/Ga)e 2 ∼1.3 as best composition at T substrate =500° C.

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Section: Methodsmentioning

confidence: 99%

Effect of Cu excess on three-stage CuGaSe2 thin films using in-situ process controls

Caballero¹,

Siebentritt²,

Sakurai³

et al. 2007

Thin Solid Films

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“…Generally, Na in CIGS improves the cell efficiency by increasing the V OC and fill factor. 97,99,100 The optimum Na dose is often considered to be equal to the amount diffusing from a soda-lime glass substrate, resulting in a typical Na concentration of approximately 0Á1 at.%.…”

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

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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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“…[2][3][4][5][6][7][8] Swiss Federal Laboratories for Materials Science and Technology (EMPA) and ZSW fabricated high-efficiency CIGSe solar cells by the evaporation process with the post deposition of alkali-metal fluorides, such as NaF, KF, and RbF. EMPA 9) and ZSW 10) fabricated high-efficiency CIGSe solar cells by the post deposition of NaF and KF and annealing in an Se atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Crystallographic, optical, and electronic properties of Li-doped CuIn(S,Se)₂, (Cu,Li)In(S,Se)₂

Kusumoto

Maeda

Wada

2018

Jpn. J. Appl. Phys.

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(Cu 1%x Li x )In(S 1%y Se y ) 2 (CLISSe) samples with 0.0 : x : 0.4 and y = 0.25, 0.50, and 0.75 were prepared by a mechanochemical process and sequential heating. The X-ray diffraction (XRD) peaks of the (Cu 1%x Li x )In(S 1%y Se y ) 2 shifted to the lower angle side by the substitution of Li atoms for Cu atoms. The solid solution limit of Li for Cu in (Cu 1%x Li x )In(S 1%y Se y ) 2 system widened with increasing Se content, y. The single-phase (Cu 1%x Li x )In(S 1%y Se y ) 2 samples were obtained for the compositions with 0.0 : x : 0.05 for y = 0.25, 0.0 : x : 0.20 for y = 0.50, and 0.0 : x : 0.30 for y = 0.75. The crystallographic parameters such as the lattice constants a and c, c/a, and the atomic coordinate of a S/Se atom for (Cu 1%x Li x )In(S 1%y Se y ) 2 were refined by Rietveld analysis using XRD data. Both the lattice constants a and c of the (Cu 1%x Li x )In(S 1%y Se y ) 2 with a tetragonal chalcopyrite structure increased with increasing Li content, x. The band gaps of (Cu 1%x Li x )In(S 1%y Se y ) 2 solid solutions widened with increasing Li content, x. To understand the band diagram of the solid solutions, the energy level of the valence band maximum (VBM) from the vacuum level was determined from the ionization energy measured by photoemission yield spectroscopy (PYS). The energy level of the conduction band minimum (CBM) was also determined by adding the band-gap energy to the VBM level. The VBM level of the (Cu 1%x Li x )In(S 0.25 Se 0.75 ) 2 solid solution decreased considerably with increasing Li content, x. The CBM level of the (Cu 1%x Li x )In(S 1%y Se y ) 2 solid solution was approximately constant. The Li doping in CuIn(S,Se) 2 is useful for decreasing the VBM of the CuIn(S,Se) 2 absorber and increasing the band-gap energy of the CuIn(S,Se) 2 absorber without increasing the CBM level.

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The effect of NaF on Cu(In,Ga)Se2 thin film solar cells

Cited by 184 publications

References 3 publications

Effect of Cu excess on three-stage CuGaSe2 thin films using in-situ process controls

Effect of Cu excess on three-stage CuGaSe2 thin films using in-situ process controls

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

Crystallographic, optical, and electronic properties of Li-doped CuIn(S,Se)₂, (Cu,Li)In(S,Se)₂

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The effect of NaF on Cu(In,Ga)Se2 thin film solar cells

Cited by 184 publications

References 3 publications

Effect of Cu excess on three-stage CuGaSe2 thin films using in-situ process controls

Effect of Cu excess on three-stage CuGaSe2 thin films using in-situ process controls

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

Crystallographic, optical, and electronic properties of Li-doped CuIn(S,Se)2, (Cu,Li)In(S,Se)2

Contact Info

Product

Resources

About

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

Crystallographic, optical, and electronic properties of Li-doped CuIn(S,Se)₂, (Cu,Li)In(S,Se)₂