Cu–Ga–In thermodynamics: experimental study, modeling, and implications for photovoltaics

Muzzillo, Christopher P.; Campbell, Carelyn E.; Anderson, Timothy J.

doi:10.1007/s10853-015-9651-3

Cited by 23 publications

(11 citation statements)

References 70 publications

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“…According to the phase diagram, Ga solubility in Cu exceeds 10 at. % at room temperature. , But, usually, thermodynamic equilibrium is not achieved after FIB milling. Hence, some accumulation of Ga at GBs is still possible and might affect the measured GB resistivity but was too low to be resolved by SEM-EDS.…”

Section: Results and Discussionmentioning

confidence: 99%

Approaches to Measure the Resistivity of Grain Boundaries in Metals with High Sensitivity and Spatial Resolution: A Case Study Employing Cu

Bishara

Ghidelli

Dehm

2020

ACS Appl. Electron. Mater.

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It is well-known that grain boundaries (GBs) increase the electrical resistivity of metals due to their enhanced electron scattering. The resistivity values of GBs are determined by their atomic structure; therefore, assessing the local resistivity of GBs is highly significant for understanding structure–property relationships. So far, the local electrical characterization of an individual GB has not received much attention, mainly due to the limited accuracy of the applied techniques, which were not sensitive enough to detect the subtle differences in electrical resistivity values of highly symmetric GBs. Here, we introduce a detailed methodology to probe in situ or ex situ the local resistivity of individual GBs in Cu, a metallic model system we choose due to its low resistance. Both bulk Cu samples and thin films are investigated, and different approaches to obtain reliable and accurate resistivity measurements are described, involving the van der Pauw technique for macroscopic measurements as well as two different four-point-probe techniques for local in situ measurements performed inside a scanning electron microscope. The in situ contacts are realized with needles accurately positioned by piezodriven micromanipulators. Resistivity results obtained on coincidence site lattice GBs (incoherent Σ3 and asymmetric Σ5) are reported and discussed. In addition, the key experimental details as well as pitfalls in the measurement of individual GB resistivity are addressed.

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Section: Results and Discussionmentioning

confidence: 99%

Approaches to Measure the Resistivity of Grain Boundaries in Metals with High Sensitivity and Spatial Resolution: A Case Study Employing Cu

Bishara

Ghidelli

Dehm

2020

ACS Appl. Electron. Mater.

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“…Previous experiments have shown that growth temperatures up to 620 °C did not require changing the composition set point, serving as indirect evidence that negligible Ga loss occurred. On the other hand, increasing growth temperature to 700 °C resulted in significantly higher Cu/Ga compositions in the final films, which is attributed to Ga loss in the form of volatile Ga 2 Se . Films with Cu/Ga of 0.31 had 10.9(1)% Cu, 33.5(2)% Ga, and 55.6(5)% Se, whereas films with Cu/Ga of 0.66 had 18.9(2)% Cu, 28.5(2)% Ga, and 52.6(5)% Se.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, increasing growth temperature to 700 °C resulted in significantly higher Cu/Ga compositions in the final films, which is attributed to Ga loss in the form of volatile Ga 2 Se. 16 Films with Cu/Ga of 0.31 had 10.9(1)% Cu, 33.5(2)% Ga, and 55. 6(5)% Se, whereas films with Cu/Ga of 0.66 had 18.9(2)% Cu, 28.5(2)% Ga, and 52.6(5)% Se.…”

Section: Methodsmentioning

confidence: 99%

Low-Cost, Efficient, and Durable H₂ Production by Photoelectrochemical Water Splitting with CuGa₃Se₅ Photocathodes

Muzzillo

Klein

et al. 2018

ACS Appl. Mater. Interfaces

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Photoelectrochemical (PEC) water splitting is an elegant method of converting sunlight and water into H fuel. To be commercially advantageous, PEC devices must become cheaper, more efficient, and much more durable. This work examines low-cost polycrystalline chalcopyrite films, which are successful as photovoltaic absorbers, for application as PEC absorbers. In particular, Cu-Ga-Se films with wide band gaps can be employed as top cell photocathodes in tandem devices as a realistic route to high efficiencies. In this report, we demonstrate that decreasing Cu/Ga composition from 0.66 to 0.31 in Cu-Ga-Se films increased the band gap from 1.67 to 1.86 eV and decreased saturated photocurrent density from 18 to 8 mA/cm as measured by chopped-light current-voltage (CLIV) measurements in a 0.5 M sulfuric acid electrolyte. Buffer and catalyst surface treatments were not applied to the Cu-Ga-Se films, and they exhibited promising stability, evidenced by unchanged CLIV after 9 months of storage in air. Finally, films with Cu/Ga = 0.36 (approximately stoichiometric CuGaSe) and 1.86 eV band gaps had exceptional durability and continuously split water for 17 days (∼12 mA/cm at -1 V vs RHE). This is equivalent to ∼17 200 C/cm, which is a world record for any polycrystalline PEC absorber. These results indicate that CuGaSe films are prime candidates for cheaply achieving efficient and durable PEC water splitting.

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“…All ternary alloys were prepared from pure elements: Ag, Cu and Ga. 30 samples (total mass about 0.50 g) were sealed and melted in evacuated quartz tubes. After alloying, the samples were homogenized in two separately operating furnaces at first at 1200°C for 10 h. Then, they were annealed in another furnace (Linn High Therm VMK 10) at 200°C (samples 1-15), 450°C (samples [16][17][18][19][20][21][22][23][24] and 650°C (samples 24-30) for 8 weeks to form equilibrium phases. After this equilibrium treatment, the tubes were quenched in cold water.…”

Section: Sem and Xrd Analysismentioning

confidence: 99%

“…[16] Recently, a new type of materials based on Cu-In-Ga-Se alloys (so-called CIGS) was developed, which is used in solar cells. [17,18] It is claimed that after Ag addition these thin film solar cells (ACIGS) reached the efficiency of almost 20%. [19] Thus, there is a mounting evidence that gallium alloys can be interesting future materials.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigations of Phase Equilibria in Ternary Ag-Cu-Ga System

Jendrzejczyk-Handzlik

Handzlik

Fitzner

2018

J. Phase Equilib. Diffus.

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Experimental study of phase equilibria in the ternary Ag-Cu-Ga system was carried out by using DTA/ DSC, isothermal equilibration and microscopic as well as x-ray analyses. DTA experiments were conducted for alloys, whose concentrations varied along two cross-sections determined by the ratio of mole fractions x Ag /x Cu-= 1:1 and x Ag /x Ga = 1:1. Equilibration of samples was carried out at 200, 450 and 650°C. The obtained information about phases in equilibrium was compared with the results of calculations of the phase diagram for conditions identical to our experiments. It was demonstrated that the results of calculations are compatible with the experimental data.

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Cu–Ga–In thermodynamics: experimental study, modeling, and implications for photovoltaics

Cited by 23 publications

References 70 publications

Approaches to Measure the Resistivity of Grain Boundaries in Metals with High Sensitivity and Spatial Resolution: A Case Study Employing Cu

Approaches to Measure the Resistivity of Grain Boundaries in Metals with High Sensitivity and Spatial Resolution: A Case Study Employing Cu

Low-Cost, Efficient, and Durable H₂ Production by Photoelectrochemical Water Splitting with CuGa₃Se₅ Photocathodes

Experimental Investigations of Phase Equilibria in Ternary Ag-Cu-Ga System

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Cu–Ga–In thermodynamics: experimental study, modeling, and implications for photovoltaics

Cited by 23 publications

References 70 publications

Approaches to Measure the Resistivity of Grain Boundaries in Metals with High Sensitivity and Spatial Resolution: A Case Study Employing Cu

Approaches to Measure the Resistivity of Grain Boundaries in Metals with High Sensitivity and Spatial Resolution: A Case Study Employing Cu

Low-Cost, Efficient, and Durable H2 Production by Photoelectrochemical Water Splitting with CuGa3Se5 Photocathodes

Experimental Investigations of Phase Equilibria in Ternary Ag-Cu-Ga System

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Low-Cost, Efficient, and Durable H₂ Production by Photoelectrochemical Water Splitting with CuGa₃Se₅ Photocathodes