Growth of single-phase Cu(In, Al)S<sub>2</sub>thin films by thermal evaporation

Smaïli, F.

doi:10.1051/epjap/2011100498

Cited by 8 publications

(7 citation statements)

References 14 publications

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“…Three solutions to the net-transfer problem have been hitherto proposed for MC materials, but they seem far from perfect. First, one could engineer a composite MC material that displays a large and constant isothermal entropy change over the target temperature span 33 , but this would be laborious and require a large number of component materials to approach perfection. Second, one could exploit serendipity under very specific circumstances, as shown using entropy-temperature data that were obtained for intermediate fields using a mean-field model 34 , but these circumstances are too restrictive to be of any practical value.…”

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confidence: 99%

“…In this paper, we demonstrate a general solution to the net-transfer problem by constructing cooling cycles in which no net heat is exchanged between a homogeneous working body of the archetypal EC material PST 2,18,[36][37][38][39] and an ideal hypothetical regenerator that it traverses in order to achieve a large temperature span T h -T c >> |T|. The underlying principle is that the two regenerator-transit legs of a given cooling cycle can be made to differ by a constant entropy if the field applied during the finite-field leg is varied according to a detailed E(T,S) map of the highly reversible phase transition at finite fields above Curie temperature T C ~ 295 K, where E denotes electric field, T denotes temperature, and S denotes entropy S after subtracting the zero-field entropy at our base temperature of 285 K. In contrast with the highly restrictive solutions discussed above [33][34][35] , our strategy for true regeneration via field variation can be readily achieved by modifying standard cooling cycles, such as Ericsson cycles. Here we modify Brayton cycles because they involve adiabatic EC effects that can be driven quickly, thus increasing cooling power and reducing heat leaks.…”

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Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range

Nair

Usui

Crossley

et al. 2019

Nature

205

132

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There is growing interest in heat pumps based on materials that show thermal changes when phase transitions are driven by changes of electric, magnetic or stress field. Importantly, regeneration permits sinks and loads to be thermally separated by many times the changes of temperature that can arise in the materials themselves. However, performance and parameterization are compromised by net heat transfer between caloric working bodies and heat-transfer fluids. Here we show that this net transfer can be avoided-resulting in true, balanced regeneration-if one varies the applied electric field while an electrocaloric (EC) working body dumps heat on traversing a passive fluid regenerator. Our EC working body is represented by bulk PbSc 0.5 Ta 0.5 O 3 (PST) near its first-order ferroelectric phase transition, where we record directly measured adiabatic temperature changes of up to 2.2 K. Indirectly measured adiabatic temperature changes of similar magnitude were identified, unlike normal, from adiabatic measurements of polarization, at nearby starting for Electrocaloric cooling cycles in lead scandium tantalate with true regeneration via field variation

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confidence: 99%

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confidence: 99%

Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range

Nair

Usui

Crossley

et al. 2019

Nature

205

132

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“…Moreover, the presence of magnetic multiphases broadens the DS M (T) curves and enhances consequently the relative cooling power (RCP) [16][17][18][19][20][21]. In this context, several magnetocaloric studies have been performed recently on composites based on manganites in order to enhance the physical properties comparing to manganites [22][23][24][25][26].…”

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confidence: 99%

Magnetocaloric effect near room temperature in (1 − y)La_0.8Ca_0.05K_0.15MnO₃/yLa_0.8K_0.2MnO₃ composites

Gargouri¹,

M'nasri²,

Cheikhrouhou‐Koubaa³

et al. 2014

Physica Status Solidi (a)

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Magnetic and magnetocaloric properties of (1 − y) La0.8Ca0.05K0.15MnO3/yLa0.8K0.2MnO3 with y = 0.25, 0.5, and 0.75 composites were investigated. Our composites will be designated by CM1 (y = 0.25), CM2 (y = 0.5), and CM3 (y = 0.75). X‐ray diffraction pattern show that La0.8Ca0.05K0.15MnO3 and La0.8K0.2MnO3 samples, elaborated using the solid state reaction at high temperature, are single phase without any detectable impurity and crystallize in the rhombohedral system with Rtrue3¯c space group. The temperature dependence of the magnetization M(T) in the temperature range 200–350 K shows that La0.8Ca0.05K0.15MnO3 and La0.8K0.2MnO3 samples exhibit a paramagnetic–ferromagnetic transition while decreasing temperature, with a Curie temperature TC increasing with K amount and reaching around 300 K for x = 0.2. The field dependence of the magnetization M(H) confirms the ferromagnetic behavior at low temperatures observed in the M(T) curves. The maximum of the magnetic entropy change ΔSnormalMmax is found to be 5.32 and 4.37 J kg−1 K−1 under a magnetic field change of 5 T for La0.8Ca0.05K0.15MnO3 and La0.8K0.2MnO3, respectively. Magnetic entropy change versus temperatures reveals that the composite CM2 with y = 0.5 exhibits the best value for the relative cooling power (RCP) of 270 J kg−1 under a magnetic field change of 5 T. For y = 0.25 and 0.75, the RCP is found to be around 227.5 J kg−1 under a magnetic field change of 5 T for both of them. The RCP value of 270 J kg−1 for CM2, which is around 66% of that observed in pure Gd makes our composite a potential candidate for magnetic refrigeration around room temperature.

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“…The average grain size of post-annealed CIAS films was evaluated from the XRD peak along the (112) preferred orientation using Scherrer's equation [6,44]:…”

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confidence: 99%

Improving the characteristics of CdS and CIAS films and the performances of CIAS solar cells by electrodeposition Cu–Se/CIAS binary structure precursors on FTO substrate

Huang

Liu

Hung

et al. 2014

J Mater Sci: Mater Electron

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Cu-poor electrodepositedCuIn 1-x Al x Se 2 (CIAS) precursor films were prepared to investigate the alteration in surface morphology of post-annealed CIAS films through post-annealing temperature adjustment. Scanning electron microscopy (SEM) and atomic force microscope (AFM) analyses demonstrated that surface morphology and root-mean-square (RMS) roughness of post-annealed CIAS films exhibited uneven and rough triangular structures. The crystal size of post-annealed CIAS films can be increased by increasing post-annealing temperature. The precursor film structure was modified by substituting Cu-Se/CIAS binary structure with CIAS single structure to proceed with the investigation. The apparent variation in surface morphology of post-annealed CIAS films changed from rough triangular structures to smooth round structures, and the RMS roughness of post-annealed CIAS films was reduced to \100 nm. The reduction was attributed to the formation of Cu-Se liquid phases during the post-annealing process, which enhanced elemental migration, recombination, and promotion of large grains and smooth surface formation. X-ray diffraction patterns showed three preferred growth orientations along the (112), (204/220), and (116/312) planes with chalcopyrite structures for all species. In addition, the characteristics of surface morphology, RMS roughness, and current measurement of subsequently deposited cadmium sulfide (CdS) film were studied and examined via SEM and AFM analyses. The surface morphology of CdS films deposited on binary structure post-annealed CIAS films exhibited smoothness, compactness, small RMS roughness, and large crystals with round and film-like structure. The AFM current images indicated that the distribution of leakage current paths was greatly diminished by changing the precursor film structure from CIAS single structure to CuSe/CIAS binary structure. The dark current-voltage characteristics of the CdS/CIAS heterojunctions showed that the reverse dark current density was decreased by approximately one order of magnitude from 4.02 9 10 -4 (single structure) to 4.26 9 10 -5 A/cm 2 (binary structure). Furthermore, the conversion efficiency of CIAS solar cells was enhanced from 0.52 (single structure) to 1.44 % (binary structure) with increase in V oc and J sc .

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Growth of single-phase Cu(In, Al)S₂thin films by thermal evaporation

Cited by 8 publications

References 14 publications

Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range

Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range

Magnetocaloric effect near room temperature in (1 − y)La_0.8Ca_0.05K_0.15MnO₃/yLa_0.8K_0.2MnO₃ composites

Improving the characteristics of CdS and CIAS films and the performances of CIAS solar cells by electrodeposition Cu–Se/CIAS binary structure precursors on FTO substrate

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Growth of single-phase Cu(In, Al)S2thin films by thermal evaporation

Cited by 8 publications

References 14 publications

Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range

Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range

Magnetocaloric effect near room temperature in (1 − y)La0.8Ca0.05K0.15MnO3/yLa0.8K0.2MnO3 composites

Improving the characteristics of CdS and CIAS films and the performances of CIAS solar cells by electrodeposition Cu–Se/CIAS binary structure precursors on FTO substrate

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Product

Resources

About

Growth of single-phase Cu(In, Al)S₂thin films by thermal evaporation

Magnetocaloric effect near room temperature in (1 − y)La_0.8Ca_0.05K_0.15MnO₃/yLa_0.8K_0.2MnO₃ composites