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Mezzi A, Bolli E, Kaciulis S, Bellucci A, Paci B, Generosi A, Mastellone M, Serpente V, Trucchi DM. Multi-Technique Approach for Work Function Exploration of Sc 2O 3 Thin Films. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1430. [PMID: 37111015 PMCID: PMC10142770 DOI: 10.3390/nano13081430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 06/19/2023]
Abstract
Thin films based on scandium oxide (Sc2O3) were deposited on silicon substrates to investigate the thickness effect on the reduction of work function. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive X-ray reflectivity (EDXR), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) measurements were performed on the films deposited by electron-beam evaporation with different nominal thicknesses (in the range of 2-50 nm) and in multi-layered mixed structures with barium fluoride (BaF2) films. The obtained results indicate that non-continuous films are required to minimize the work function (down to 2.7 eV at room temperature), thanks to the formation of surface dipole effects between crystalline islands and substrates, even if the stoichiometry is far from the ideal one (Sc/O = 0.38). Finally, the presence of BaF2 in multi-layered films is not beneficial for a further reduction in the work function.
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Affiliation(s)
- Alessio Mezzi
- Institute for the Study of Nanostructured Materials, ISMN-CNR, Montelibretti, 00010 Rome, Italy
| | - Eleonora Bolli
- Institute of Structure of Matter, DiaTHEMA Lab, ISM-CNR, Montelibretti, 00010 Rome, Italy
| | - Saulius Kaciulis
- Institute for the Study of Nanostructured Materials, ISMN-CNR, Montelibretti, 00010 Rome, Italy
| | - Alessandro Bellucci
- Institute of Structure of Matter, DiaTHEMA Lab, ISM-CNR, Montelibretti, 00010 Rome, Italy
| | - Barbara Paci
- Institute of Structure of Matter, ISM-CNR, 00133 Rome, Italy
| | - Amanda Generosi
- Institute of Structure of Matter, ISM-CNR, 00133 Rome, Italy
| | - Matteo Mastellone
- Institute of Structure of Matter, DiaTHEMA Lab, ISM-CNR, Montelibretti, 00010 Rome, Italy
| | - Valerio Serpente
- Institute of Structure of Matter, DiaTHEMA Lab, ISM-CNR, Montelibretti, 00010 Rome, Italy
| | - Daniele Maria Trucchi
- Institute of Structure of Matter, DiaTHEMA Lab, ISM-CNR, Montelibretti, 00010 Rome, Italy
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Mastellone M, Pace ML, Curcio M, Caggiano N, De Bonis A, Teghil R, Dolce P, Mollica D, Orlando S, Santagata A, Serpente V, Bellucci A, Girolami M, Polini R, Trucchi DM. LIPSS Applied to Wide Bandgap Semiconductors and Dielectrics: Assessment and Future Perspectives. MATERIALS 2022; 15:ma15041378. [PMID: 35207919 PMCID: PMC8880014 DOI: 10.3390/ma15041378] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/04/2022] [Accepted: 02/09/2022] [Indexed: 02/04/2023]
Abstract
With the aim of presenting the processes governing the Laser-Induced Periodic Surface Structures (LIPSS), its main theoretical models have been reported. More emphasis is given to those suitable for clarifying the experimental structures observed on the surface of wide bandgap semiconductors (WBS) and dielectric materials. The role played by radiation surface electromagnetic waves as well as Surface Plasmon Polaritons in determining both Low and High Spatial Frequency LIPSS is briefly discussed, together with some experimental evidence. Non-conventional techniques for LIPSS formation are concisely introduced to point out the high technical possibility of enhancing the homogeneity of surface structures as well as tuning the electronic properties driven by point defects induced in WBS. Among these, double- or multiple-fs-pulse irradiations are shown to be suitable for providing further insight into the LIPSS process together with fine control on the formed surface structures. Modifications occurring by LIPSS on surfaces of WBS and dielectrics display high potentialities for their cross-cutting technological features and wide applications in which the main surface and electronic properties can be engineered. By these assessments, the employment of such nanostructured materials in innovative devices could be envisaged.
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Affiliation(s)
- Matteo Mastellone
- ISM-CNR, DiaTHEMA Laboratory, U.O.S. Montelibretti, Via Salaria km 29.300, 00015 Monterotondo, Italy; (M.M.); (V.S.); (A.B.); (M.G.); (R.P.); (D.M.T.)
| | - Maria Lucia Pace
- ISM-CNR, FemtoLAB, U.O.S. Tito Scalo, Zona Industriale, 85050 Potenza, Italy; (M.L.P.); (P.D.); (D.M.); (S.O.)
| | - Mariangela Curcio
- Dipartimento di Scienze, Università della Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (N.C.); (A.D.B.); (R.T.)
| | - Nicola Caggiano
- Dipartimento di Scienze, Università della Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (N.C.); (A.D.B.); (R.T.)
| | - Angela De Bonis
- Dipartimento di Scienze, Università della Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (N.C.); (A.D.B.); (R.T.)
| | - Roberto Teghil
- Dipartimento di Scienze, Università della Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy; (M.C.); (N.C.); (A.D.B.); (R.T.)
| | - Patrizia Dolce
- ISM-CNR, FemtoLAB, U.O.S. Tito Scalo, Zona Industriale, 85050 Potenza, Italy; (M.L.P.); (P.D.); (D.M.); (S.O.)
| | - Donato Mollica
- ISM-CNR, FemtoLAB, U.O.S. Tito Scalo, Zona Industriale, 85050 Potenza, Italy; (M.L.P.); (P.D.); (D.M.); (S.O.)
| | - Stefano Orlando
- ISM-CNR, FemtoLAB, U.O.S. Tito Scalo, Zona Industriale, 85050 Potenza, Italy; (M.L.P.); (P.D.); (D.M.); (S.O.)
| | - Antonio Santagata
- ISM-CNR, FemtoLAB, U.O.S. Tito Scalo, Zona Industriale, 85050 Potenza, Italy; (M.L.P.); (P.D.); (D.M.); (S.O.)
- Correspondence: ; Tel.: +39-0971427227
| | - Valerio Serpente
- ISM-CNR, DiaTHEMA Laboratory, U.O.S. Montelibretti, Via Salaria km 29.300, 00015 Monterotondo, Italy; (M.M.); (V.S.); (A.B.); (M.G.); (R.P.); (D.M.T.)
| | - Alessandro Bellucci
- ISM-CNR, DiaTHEMA Laboratory, U.O.S. Montelibretti, Via Salaria km 29.300, 00015 Monterotondo, Italy; (M.M.); (V.S.); (A.B.); (M.G.); (R.P.); (D.M.T.)
| | - Marco Girolami
- ISM-CNR, DiaTHEMA Laboratory, U.O.S. Montelibretti, Via Salaria km 29.300, 00015 Monterotondo, Italy; (M.M.); (V.S.); (A.B.); (M.G.); (R.P.); (D.M.T.)
| | - Riccardo Polini
- ISM-CNR, DiaTHEMA Laboratory, U.O.S. Montelibretti, Via Salaria km 29.300, 00015 Monterotondo, Italy; (M.M.); (V.S.); (A.B.); (M.G.); (R.P.); (D.M.T.)
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma ‘Tor Vergata’, 00133 Rome, Italy
| | - Daniele Maria Trucchi
- ISM-CNR, DiaTHEMA Laboratory, U.O.S. Montelibretti, Via Salaria km 29.300, 00015 Monterotondo, Italy; (M.M.); (V.S.); (A.B.); (M.G.); (R.P.); (D.M.T.)
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Zhang X, Sin Ang Y, Ang LK, Chen J. Concentrated thermionic solar cells using graphene as the collector: theoretical efficiency limit and design rules. NANOTECHNOLOGY 2021; 33:065404. [PMID: 34710863 DOI: 10.1088/1361-6528/ac3459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
We propose an updated design on concentrated thermionic emission solar cells, which demonstrates a high solar-to-electricity energy conversion efficiency larger than 10% under 600 suns, by harnessing the exceptional electrical, thermal, and radiative properties of the graphene as a collector electrode. By constructing an analytical model that explicitly takes into account the non-Richardson behavior of the thermionic emission current from graphene, space charge effect in vacuum gap, and the various irreversible energy losses within the subcomponents, we perform detailed characterizations on the conversion efficiency limit and parametric optimum design of the proposed system. Under 800 suns, a maximum efficiency of 12.8% has been revealed, where current density is 3.87 A cm-2, output voltage is 1.76 V, emitter temperature is 1707 K, and collector temperature is 352 K. Moreover, we systematically compare the peak efficiencies of various configurations combining diamond or graphene, and show that utilizing diamond films as an emitter and graphene as a collector offers the highest conversion efficiency, thus revealing the important role of graphene in achieving high-performance thermionic emission solar cells. This work thus opens up new avenues to advance the efficiency limit of thermionic solar energy conversion and the development of next-generation novel-nanomaterial-based solar energy harvesting technology.
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Affiliation(s)
- Xin Zhang
- School of Science, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Yee Sin Ang
- Science, Mathematics and Technology, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Lay Kee Ang
- Science, Mathematics and Technology, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Jincan Chen
- Department of Physics, Xiamen University, Xiamen 361005, People's Republic of China
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Semiconductor thermionics for next generation solar cells: photon enhanced or pure thermionic? Nat Commun 2021; 12:4622. [PMID: 34330924 PMCID: PMC8324797 DOI: 10.1038/s41467-021-24891-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 07/08/2021] [Indexed: 11/16/2022] Open
Abstract
Semiconductors have been used in solar energy conversion for decades based on the photovoltaic effect. An important challenge of photovoltaics is the undesired heat generated within the device. An alternative approach is thermionics, which uses the thermal excitation of electrons from an emitter to a collector across a vacuum gap. If the emitter is a p-type semiconductor, the photogeneration-induced quasi-Fermi level splitting can reduce the effective barrier for electron emission—a mechanism used by a photon enhanced thermionic emission device. Here, we evaluate the prospects of this alternative solar conversion technology considering different semiconductor materials and thermionic device configurations. We also reveal that whether such a device operates in the photon enhanced or purely thermionic mode, depends on the complex interplay among materials properties, device physics and solar concentration level. A semiconductor thermionic device, which utilises thermally excited electrons, is considered as an alternative in solar conversion technology, yet its working mechanism is not clear. Here, the authors reveal that whether such a device operates in the photon enhanced or purely thermionic mode, greatly depends on the material properties and device physics.
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