Pulsed Electron-Beam Deposition of High Temperature Superconducting Films for Coated Conductor Applications

Abstract:The quest for single-stage deposition of CuInGaSe 2 (CIGS) is an open race to replace very effective but capital intensive thin film solar cell manufacturing processes like multiple-stage coevaporation or sputtering combined with high pressure selenisation treatments. In this paper the most recent achievements of Low Temperature Pulsed Electron Deposition (LTPED), a novel single stage deposition process by which CIGS can be deposited at 250˝C, are presented and discussed. We show that selenium loss during the film deposition is not a problem with LTPED as good crystalline films are formed very close to the melting temperature of selenium. The mechanism of formation of good ohmic contacts between CIGS and Mo in the absence of any MoSe 2 transition layers is also illustrated, followed by a brief summary of the measured characteristics of test solar cells grown by LTPED. The 17% efficiency target achieved by lab-scale CIGS devices without bandgap modulation, antireflection coating or K-doping is considered to be a crucial milestone along the path to the industrial scale-up of LTPED. The paper ends with a brief review of the open scientific and technological issues related to the scale-up and the possible future applications of the new technology.

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“…This is in agreement with published results on multiple-source pulsed electron deposition of superconducting films [24].…”

Section: Efficiency and Uniformity Of Solar Cellssupporting

confidence: 93%

Progress on Low-Temperature Pulsed Electron Deposition of CuInGaSe2 Solar Cells

et al. 2016

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“…The reported experimental value of the ablation depth has been estimated to be around 1.0 µm [5,17]. This is in good accordance with the ablation depth of 0.75 µm obtained from the model based on melting as illustrated in figure 3.…”

Section: Model Assessmentsupporting

confidence: 87%

“…To assess the validity of the model, appropriate parameters calculated from the model have been contrasted with available experimental results, under the prevailing conditions of this study, in the literature [5,[17][18][19]. The reported experimental value of the ablation depth has been estimated to be around 1.0 µm [5,17].…”

Section: Model Assessmentmentioning

confidence: 99%

“…This causes a quick vaporization, as a result of non-equilibrium heating, of a small portion of the target surface and ensuing plasma plume expansion toward a substrate. Accordingly, thin films with superior properties can be deposited at a considerably lower substrate temperature compared to other deposition techniques such as single stage co-evaporation or sputtering [5]. PEBA offers several attractive advantages over PLA, but one of the most distinguishing capabilities is its ability to ablate a wide range of materials, including optically transparent or reflective materials, owing to the electrons shorter absorption depth as compared to photons [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, thin films with superior properties can be deposited at a considerably lower substrate temperature compared to other deposition techniques such as single stage co-evaporation or sputtering [5]. PEBA offers several attractive advantages over PLA, but one of the most distinguishing capabilities is its ability to ablate a wide range of materials, including optically transparent or reflective materials, owing to the electrons shorter absorption depth as compared to photons [4][5][6]. It is has been demonstrated experimentally that pulsed electron beam ablation can be an efficient technique for the synthesis of thin films, nanostructures and clusters [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Modelling of pulsed electron beam induced graphite ablation: Sublimation versus melting

Ali

Henda

2017

J. Phys.: Conf. Ser.

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Abstract. Pulsed electron beam ablation (PEBA) has recently emerged as a very promising technique for the deposition of thin films with superior properties. Interaction of the pulsed electron beam with the target material is a complex process, which consists of heating, phase transition, and erosion of a small portion from the target surface. Ablation can be significantly affected by the nature of thermal phenomena taking place at the target surface, with subsequent bearing on the properties, stoichiometry and structure of deposited thin films. A two stage, onedimensional heat conduction model is presented to describe two different thermal phenomena accounting for interaction of a graphite target with a polyenergetic electron beam. In the first instance, the thermal phenomena are comprised of heating, melting and vaporization of the target surface, while in the second instance the thermal phenomena are described in terms of heating and sublimation of the graphite surface. In this work, the electron beam delivers intense electron pulses of ~100 ns with energies up to 16 keV and an electric current of ~400 A to a graphite target. The temperature distribution, surface recession velocity, ablated mass per unit area, and ablation depth for the graphite target are numerically simulated by the finite element method for each case. Based on calculation findings and available experimental data, ablation appears to occur mainly in the regime of melting and vaporization from the surface.

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