Synthesis and Technological Application of Electrodeposited Semiconductors by EC-ALD

Giaccherini, Andrea; Bencistà, Ilaria; Cinotti, Serena; Montegrossi, Giordano; Guerri, Annalisa; Benedetto, Francesco Di; Lavacchi, Alessandro; Foresti, Maria Luisa; Felici, Roberto; Carlà, Francesco; Innocenti, Massimo

doi:10.1149/05832.0035ecst

Cited by 6 publications

(14 citation statements)

References 11 publications

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“…The dependence of the intensity along the l direction shows that the rings are due to phases almost perfectly oriented along the [0 0 1] direction. The reflections present as Bragg peaks have a periodicity and structure comparable to an ordered phase of Cu 2 S, already reported by our group elsewhere [16,17,33]. The operando crystallographic structure of the grown Cu 2 S films has strong similarities with the one of the low chalcocite [16,17,33], although the in-plane lattice parameters point to a different metric [21].…”

Section: Maps 1:1supporting

confidence: 74%

“…4. Among the most intense, this peak has no overlapping with other signals and provides very reliable information [21,33]. The coordinates of this peak refer to a Cu 2 S chalcocite-like crystal structure previously found in other studies.…”

Section: Single Line Profile Analysissupporting

confidence: 67%

“…The set of pseudo-single crystal Bragg reflections has been assigned to the Cu 2 S (chalcocite type) phase already reckoned during the operando SXRD study of the E-ALD grown binary copper sulfide [33,34]. The growth of the ordered phase is simultaneously accompanied by the formation of a disordered Cu 2 S phase, this latter fully coincident with the natural low temperature chalcocite polymorph, the presence of which is also confirmed by the Debye rings present in the map of Fig.…”

Section: Discussionsupporting

confidence: 55%

“…2 and 3), point out that ordered (pseudo-single crystal) and disordered polycrystalline phases are occurring in the sample Op1:1, as well as that the final product do contains two different Cu 2 S phases, with different structural arrangements, and wurtzite ZnS. This evidence apparently contrasts what already observed on other binary sulphides, including the Cu 2 S itself [33,34], and the ternary Zn-Cd-S films [14,15].…”

Section: Discussionmentioning

confidence: 70%

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Operando SXRD of E-ALD deposited sulphides ultra-thin films: Crystallite strain and size

Giaccherini

Russo

Carlà

et al. 2018

Applied Surface Science

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a b s t r a c tElectrochemical Atomic Layer Deposition (E-ALD), exploiting surface limited electrodeposition of atomic layers, can easily grow highly ordered ultra-thin films and 2D structures. Among other compounds Cu x Zn y S grown by means of E-ALD on Ag(111) has been found particularly suitable for the solar energy conversion due to its band gap (1.61 eV). However its growth seems to be characterized by a micrometric thread-like structure, probably overgrowing a smooth ultra-thin films. On this ground, a SXRD investigation has been performed, to address the open questions about the structure and the growth of Cu x Zn y S by means of E-ALD. The experiment shows a pseudo single crystal pattern as well as a powder pattern, confirming that part of the sample grows epitaxially on the Ag(111) substrate. The growth of the film was monitored by following the evolution of the Bragg peaks and Debye rings during the E-ALD steps. Breadth and profile analysis of the Bragg peaks lead to a qualitative interpretation of the growth mechanism. This study confirms that Zn lead to the growth of a strained Cu 2 S-like structure, while the growth of the thread-like structure is probably driven by the release of the stress from the epitaxial phase.

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Section: Maps 1:1supporting

confidence: 74%

Section: Single Line Profile Analysissupporting

confidence: 67%

Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 70%

See 2 more Smart Citations

Operando SXRD of E-ALD deposited sulphides ultra-thin films: Crystallite strain and size

Giaccherini

Russo

Carlà

et al. 2018

Applied Surface Science

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“…Still, in some cases, different authors found compositional, structural or morphological features conflicting with these assumptions, in particular when growing metal chalcogenides ultra-thin films of practical thickness: a) Unexpected film thickness: 30 E-ALD cycles of CdS are reported to have half the expected thickness 8 b) Unexpected surface morphology: micrometric scale thread-like structure for the growth of ternary sulfide of copper and zinc (Cu x Zn y S) 14,[16][17][18] . c) Unexpected chemical composition: the E-ALD growth of copper sulfide results in a Cu:S ratio of 2:1 (Cu 2 S) instead of 1:1 (CuS) 19,20 . Similarly, for the growth of Cu x Zn y S, the expected Cu:Zn ratio was 1:1 while the experimental ratio is 6:1 14,[16][17][18] .…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Thermochemistry of the E-ALD process for the growth of CuxZnyS on Ag(111): Interpretation of experimental data

Giaccherini

Montegrossi

Benedetto

et al. 2018

Electrochimica Acta

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The electrochemical atomic layer deposition (E-ALD) growth of chalcogenides materials enables the deposition of technologically interesting ultra-thin films. However, this method raises some questions about the actual growth mechanism. We addressed one of the more interesting anomalies reported lately: the occurrence of the Zn-deficiency and of the polycrystalline thread-like overgrown structures in the E-ALD growth of Cu x Zn y S. The present study was developed using a computational speciation approach under the mass balance method. Exploiting a well-established computational approach, but uncommonly applied to the electrochemical science, we calculated the predominance charts and the equilibrium speciation of the solid phases during the electrochemical process. On this basis, we obtained a deep insight into the mechanism underlying the E-ALD process from a thermodynamic standpoint. Thus, we identified the crucial steps of the Cu x Zn y S growth leading to the anomalies object of this research.

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Atomic Layer Deposition of Conducting CuS Thin Films from Elemental Sulfur

Tripathi

Lahtinen

Karppinen

2018

Adv Materials Inter

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Copper sulfide thin films have been fabricated by various deposition techniques, such as chemical vapor deposition, [15] sputtering, spray pyrolysis, [16,17] chemical bath deposition, [18,19] and electrochemical methods. [20][21][22] However, in most cases the required control over the film stoichiometry and phase composition is poorly achieved due to the coexistence of several stable and metastable copper sulfide phases. [23] Moreover, fabrication of continuous copper sulfide coatings with a well-controlled morphology on highaspect-ratio nanostructures has remained a challenge. It is here in particular where the atomic layer deposition (ALD) technique could provide us with clear advantages over the other thin-film technologies for the deposition of high-quality copper sulfide thin films for various advanced applications including the photovoltaics. [17,24,25] Atomic layer deposition is based on sequential and self-limiting gas-surface reactions and is known to yield exceptionally homogeneous coatings in atomic-scale precision independent of the substrate geometry.The vast majority of the metal sulfide ALD processes is based on metal-organic precursors together with hydrogen sulfide H 2 S as the source of sulfur; [26] the same applies to the reported copper sulfide ALD processes as well (see Table 1). The main merit of H 2 S is that it is highly reactive toward common metal precursors. However, H 2 S is a flammable, corrosive, and highly toxic gas, and its incorporation in the ALD technology presents several serious technical challenges. The special precautions required for the safe use of H 2 S may even be one of the reasons why only 16 metal sulfide ALD processes have been so far reported during the half a century long ALD history. [26] Another drawback of the H 2 S-based ALD processes is the slowness of these processes, see, e.g., the growth rate values given in Table 1 for the copper sulfide processes. Moreover, majority of the reported copper sulfide processes yields Cu(I) sulfide as the main phase; hence, there is a clear interest in a new robust and efficient ALD process for high-quality Cu(II) sulfide thin films. [27] Despite the fact that some of the early ALD processes employed elemental sulfur instead of H 2 S as the sulfur source, [35] to the best of our knowledge no sulfur-based ALD processes have been reported for copper sulfide thin films. Here, we present a simple and efficient low-temperature ALD process for the deposition of high-quality p-type conducting CuS thin films from copper acetyl acetonate and elemental sulfur precursors, as a highly viable solution to the challenges discussed above.A facile, yet precisely controlled and efficient atomic layer deposition (ALD) process is reported for high-quality copper(II) sulfide thin films based on elemental solid sulfur as the source for sulfur; Cu(acac) 2 (acac: acetylacetonate) is used as the copper precursor. In the deposition temperature range as low as 140-160 °C, the process proceeds in an essentially ideal ALD manner and yields single-phase C...

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Synthesis and Technological Application of Electrodeposited Semiconductors by EC-ALD

Cited by 6 publications

References 11 publications

Operando SXRD of E-ALD deposited sulphides ultra-thin films: Crystallite strain and size

Operando SXRD of E-ALD deposited sulphides ultra-thin films: Crystallite strain and size

Thermochemistry of the E-ALD process for the growth of CuxZnyS on Ag(111): Interpretation of experimental data

Atomic Layer Deposition of Conducting CuS Thin Films from Elemental Sulfur

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