Doping of chalcopyrites by hydrogen

Kılıç, Çetin; Zunger, Alex

doi:10.1063/1.1608494

Cited by 18 publications

(5 citation statements)

References 21 publications

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“…Therefore, one can expect that H atoms quench the V Cu present in the top few layers of the CISe surface or form a H–Se bond at the surface. It is to be noted that our results are in a qualitative agreement with those of Kılıç and Zunger, which indicated that H-related defects are either detrimental to the p-type conductivity or can neutralize the p typeness of CISe.…”

Section: Resultssupporting

confidence: 90%

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Theoretical Investigation of the Interaction of the CuInSe₂ Absorber Material with Oxygen, Hydrogen, and Water

et al. 2018

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We performed ab initio calculations to study oxygen and hydrogen point defects in the CuInSe 2 (CISe) solar-cell material. We found that H interstitial defects (when one H atom is surrounded by four Se atoms) and H Cu (when a H atom is replacing a Cu atom) are the most stable defects. Whereas these H substitutional defects remain neutral, H interstitial defects act as donor defects and are detrimental to the cell performance. The incorporation of H 2 into the CISe lattice, on the other hand, is harmless to the p-type conductivity. Oxygen atoms tend to either substitute Se atoms in the CISe lattice or form interstitial defects, though the formation of substitutional defects is more favorable. All oxygen point defects have high formation energies, which results in a low concentration of these defects in CISe. However, the presence of oxygen in the system leads to the formation of secondary phases such as In 2 O 3 and InCuO 2 . In addition to the point defects, we studied the adsorption of H 2 O molecules on a defect-free surface and a surface with a (2V Cu + In Cu ) defect using the ab initio thermodynamics technique. Our results indicate that the dissociative water adsorption on the CISe surface is energetically unfavorable. Furthermore, in order to obtain a water-free surface, the surface with defects has to be calcined at a higher temperature compared to the defect-free surface.

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Section: Resultssupporting

confidence: 90%

“…Our results show that among H substitutional point defects, H Cu has the lowest Δ E f . This is similar to other impurities such as Na and K, where Na Cu and K Cu substitutional defects were the most favorable defects in Cu-poor CISe. , …”

Section: Resultssupporting

confidence: 77%

Theoretical Investigation of the Interaction of the CuInSe₂ Absorber Material with Oxygen, Hydrogen, and Water

et al. 2018

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“…The calculated defect formation energies suggested that interstitial hydrogen can be the source of n-type conductivity, with its E(+/-) charge-transition level (also known as pinning level) lying inside the conduction band. In contrast, hydrogen in CGS was predicted to be a charge-compensating defect with the E(+/-) level positioned well inside the gap [6,10,11]. The more recent results placed this level at about 0.5 eV below the conduction-band edge [6].…”

Section: Introductionmentioning

confidence: 95%

“…The electrical activity of hydrogen in the ternary CIS and CuGaSe 2 (CGS) chalcopyrite compounds has been thoroughly studied in the past by first-principles approaches [6,10,11] based on density-functional theory [12,13]. For CIS the most recent study by Varley and coworkers [6] made use of the HSE06 hybrid functional [14][15][16], a choice that enabled a trusted reproduction of the experimental electronic gap.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen states in mixed-cation CuIn_(1−x)Ga_xSe₂ chalcopyrite alloys: a combined study by first-principles density-functional calculations and muon-spin spectroscopy

Marinopoulos

Vilão

Alberto

et al. 2021

Philosophical Magazine

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First-principles calculations were performed jointly with muon-spin (µSR) spectroscopy experiments in order to examine the electrical activity of hydrogen in mixed-cation chalcopyrite Cu(In1−x,Gax)Se2 (CIGS) alloys and other related compounds commonly used as absorbers in solar-cell technology. The study targeted the range of Ga concentrations most relevant in typical solar cells. By means of a hybridfunctional approach the charge-transition levels of hydrogen were determined and the evolution of the defect pinning level, E(+/-), was monitored as a function of the Ga content. The use of E(+/-) as a metric of the charge-neutrality level allowed the alignment of band structures, thus providing the band offsets between the CuInSe2 compound and the CIGS alloys. The µSR measurements in both thin-film and bulk CIGS materials confirmed that the positively-charged state is the thermodynamically stable configuration of hydrogen for p-type conditions. The interpretation of the µSR data further addressed the existence of a metastable quasi-atomic neutral configuration that was resolved from the calculations and led to a formation model for muon implantation.

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“…At low temperatures (below around 150 K), however, a fraction between 20% and 40% of the muons may also form a neutral state in an interstitial position. First-principle calculations in Cu(In,Ga)Se 2 [23,24] found that H + takes up an equilibrium position at the Cu-Se bond-center site close to the Se atom, whereas H 0 and H − occupy equilibrium positions at the interstitial site next to In or Ga.…”

Section: Introductionmentioning

confidence: 99%

Slow-muon study of quaternary solar-cell materials: Single layers and p−n junctions

Alberto

Vilão

Vieira

et al. 2018

Phys. Rev. Materials

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Thin films and p-n junctions for solar cells based on the absorber materials Cu(In,Ga)Se 2 and Cu 2 ZnSnS 4 were investigated as a function of depth using implanted low energy muons. The most significant result is a clear decrease of the formation probability of the Mu + state at the heterojunction interface as well as at the surface of the Cu(In,Ga)Se 2 film. This reduction is attributed to a reduced bonding reaction of the muon in the absorber defect layer at its surface. In addition, the activation energies for the conversion from a muon in an atomiclike configuration to a anion-bound position are determined from temperature-dependence measurements. It is concluded that the muon probe provides a measurement of the effective surface defect layer width, both at the heterojunctions and at the films. The CIGS surface defect layer is crucial for solar-cell electrical performance and additional information can be used for further optimizations of the surface.

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Doping of chalcopyrites by hydrogen

Cited by 18 publications

References 21 publications

Theoretical Investigation of the Interaction of the CuInSe₂ Absorber Material with Oxygen, Hydrogen, and Water

Theoretical Investigation of the Interaction of the CuInSe₂ Absorber Material with Oxygen, Hydrogen, and Water

Hydrogen states in mixed-cation CuIn_(1−x)Ga_xSe₂ chalcopyrite alloys: a combined study by first-principles density-functional calculations and muon-spin spectroscopy

Slow-muon study of quaternary solar-cell materials: Single layers and p−n junctions

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Doping of chalcopyrites by hydrogen

Cited by 18 publications

References 21 publications

Theoretical Investigation of the Interaction of the CuInSe2 Absorber Material with Oxygen, Hydrogen, and Water

Theoretical Investigation of the Interaction of the CuInSe2 Absorber Material with Oxygen, Hydrogen, and Water

Hydrogen states in mixed-cation CuIn(1−x)GaxSe2 chalcopyrite alloys: a combined study by first-principles density-functional calculations and muon-spin spectroscopy

Slow-muon study of quaternary solar-cell materials: Single layers and p−n junctions

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Theoretical Investigation of the Interaction of the CuInSe₂ Absorber Material with Oxygen, Hydrogen, and Water

Theoretical Investigation of the Interaction of the CuInSe₂ Absorber Material with Oxygen, Hydrogen, and Water

Hydrogen states in mixed-cation CuIn_(1−x)Ga_xSe₂ chalcopyrite alloys: a combined study by first-principles density-functional calculations and muon-spin spectroscopy