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Publications (9 of 9) Show all publications
Tahira, A., Mazzaro, R., Rigoni, F., Nafady, A., Shaikh, S. F., Alothman, A. A., . . . Ibupoto, Z. H. (2021). A simple and efficient visible light photodetector based on Co3O4/ZnO composite. Optical and quantum electronics, 53(9), Article ID 534.
Open this publication in new window or tab >>A simple and efficient visible light photodetector based on Co3O4/ZnO composite
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2021 (English)In: Optical and quantum electronics, ISSN 0306-8919, E-ISSN 1572-817X, Vol. 53, no 9, article id 534Article in journal (Refereed) Published
Abstract [en]

Herein, we propose for the first time visible light photodetector based on n-type ZnO nanorods decorated with p-type Co3O4 nanowires. The heterojunction was fabricated on fluorine doped tin oxide (FTO) glass substrate by low temperature aqueous chemical growth method. ZnO exhibits nanorod morphology and cobalt oxide possesses nanowire shape with sharp tail. Energy dispersive spectroscopy confirmed the presence of Zn, O, and Co elements in the heterojunction. ZnO and Co3O4 have hexagonal and cubic phases, respectively, as confirmed by XRD. The dense and perpendicular ZnO nanorods are acting as a scattering layer for visible light, while Co3O4 nanowires act as a visible-light absorber. The all oxide p–n junction can operate as visible light photodetector. Furthermore, the heterojunction also shows a reproducible and fast response for the detection of visible light. Optimization of the device is needed (presence of buffer layers, tuning a thickness of the optical absorber) to improve its functionalities. 

Place, publisher, year, edition, pages
Springer Nature, 2021
Keywords
ZnO nanorods, Co3O4 nanosheets, Heterojunction, Visible light photodetector
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-86982 (URN)10.1007/s11082-021-03129-x (DOI)000690987400001 ()2-s2.0-85113418254 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-09-07 (alebob);

Forskningsfinansiär: King Saud University (RSP-2021/79)

Available from: 2021-09-06 Created: 2021-09-06 Last updated: 2021-09-07Bibliographically approved
Dobryden, I., Borgani, R., Rigoni, F., Ghamgosar, P., Concina, I., Almqvist, N. & Vomiero, A. (2021). Nanoscale characterization of an all-oxide core-shell nanorod heterojunction using intermodulation atomic force microscopy (AFM) methods. Nanoscale Advances, 3(15), 4388-4394
Open this publication in new window or tab >>Nanoscale characterization of an all-oxide core-shell nanorod heterojunction using intermodulation atomic force microscopy (AFM) methods
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2021 (English)In: Nanoscale Advances, E-ISSN 2516-0230, Vol. 3, no 15, p. 4388-4394Article in journal (Refereed) Published
Abstract [en]

The electrical properties of an all-oxide core–shell ZnO–Co3O4 nanorod heterojunction were studied in the dark and under UV-vis illumination. The contact potential difference and current distribution maps were obtained utilizing new methods in dynamic multifrequency atomic force microscopy (AFM) such as electrostatic and conductive intermodulation AFM. Light irradiation modified the electrical properties of the nanorod heterojunction. The new techniques are able to follow the instantaneous local variation of the photocurrent, giving a two-dimensional (2D) map of the current–voltage curves and correlating the electrical and morphological features of the heterostructured core–shell nanorods.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2021
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-85199 (URN)10.1039/d1na00319d (DOI)000657788200001 ()2-s2.0-85111592982 (Scopus ID)
Funder
The Kempe FoundationsKnut and Alice Wallenberg Foundation
Note

Validerad;2021;Nivå 2;2021-08-12 (alebob)

Available from: 2021-06-10 Created: 2021-06-10 Last updated: 2023-09-05Bibliographically approved
Alvi, S. A., Ghamgosar, P., Rigoni, F., Vomiero, A. & Akhtar, F. (2019). Adaptive nanolaminate coating by atomic layer deposition. Thin Solid Films, 692, Article ID 137631.
Open this publication in new window or tab >>Adaptive nanolaminate coating by atomic layer deposition
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2019 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 692, article id 137631Article in journal (Refereed) Published
Abstract [en]

Atomic layer deposition (ALD) was used to deposit ZnO/Al2O3/V2O5 nanolaminate coatings to demonstrate a coating system with temperature adaptive frictional behaviour. The nanolaminate coating exhibited excellent conformity and crack-free coating of thickness 110 nm over Inconel 718 substrate. The ALD trilayer coating showed a hardness and elastic modulus of 12 GPa and 193 GPa, respectively. High-temperature tribology of the nanolaminate trilayer was tested against steel ball in dry sliding condition at 25 °C (room temperature, RT), 200 °C, 300 °C, and 400 °C. It was found that the nanolaminate coating showed a low coefficient of friction (COF) and wear rate at RT and 300 °C. The trilayer coating was found intact and stable at all temperatures during the friction tests. The adaptability of nanolaminate coating with the temperature was verified by performing the cyclic friction test at 300 °C and RT. The low COF and wear rate had been attributed to the (100) and (002) basal plane sliding of ZnO top layer, and the interlayer sliding of weakly bonded planes parallel to (001) plane in V2O5 bottom layer. Furthermore, even after the removal of ZnO coating during the tribotest, the bottom V2O5 layer coating stabilized the COF and wear rate at RT and 300 °C.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Atomic layer deposition, Nanolaminate coating, Tribology, High temperature, Adaptive coating
National Category
Other Physics Topics Other Materials Engineering
Research subject
Experimental Physics; Engineering Materials
Identifiers
urn:nbn:se:ltu:diva-76604 (URN)10.1016/j.tsf.2019.137631 (DOI)000499678700001 ()2-s2.0-85075506757 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-12-09 (johcin)

Available from: 2019-11-04 Created: 2019-11-04 Last updated: 2021-10-15Bibliographically approved
Ghamgosar, P., Rigoni, F., Gilzad Kohan, M., You, S., Morales, E. A., Mazzaro, R., . . . Vomiero, A. (2019). Self-Powered Photodetectors Based on Core-Shell ZnO-Co3O4 Nanowire Heterojunctions. ACS Applied Materials and Interfaces, 11(26), 23454-23462
Open this publication in new window or tab >>Self-Powered Photodetectors Based on Core-Shell ZnO-Co3O4 Nanowire Heterojunctions
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2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 26, p. 23454-23462Article in journal (Refereed) Published
Abstract [en]

Self-powered photodetectors operating in the UV–visible–NIR window made of environmentally friendly, earth abundant, and cheap materials are appealing systems to exploit natural solar radiation without external power sources. In this study, we propose a new p–n junction nanostructure, based on a ZnO–Co3O4 core–shell nanowire (NW) system, with a suitable electronic band structure and improved light absorption, charge transport, and charge collection, to build an efficient UV–visible–NIR p–n heterojunction photodetector. Ultrathin Co3O4 films (in the range 1–15 nm) were sputter-deposited on hydrothermally grown ZnO NW arrays. The effect of a thin layer of the Al2O3 buffer layer between ZnO and Co3O4 was investigated, which may inhibit charge recombination, boosting device performance. The photoresponse of the ZnO–Al2O3–Co3O4 system at zero bias is 6 times higher compared to that of ZnO–Co3O4. The responsivity (R) and specific detectivity (D*) of the best device were 21.80 mA W–1and 4.12 × 1012 Jones, respectively. These results suggest a novel p–n junction structure to develop all-oxide UV–vis photodetectors based on stable, nontoxic, low-cost materials.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
ZnO−CoO core−shell, all-oxide p−n heterojunction, nanowire geometry, photovoltaic photodetector, self-powered photodetector
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-75216 (URN)10.1021/acsami.9b04838 (DOI)000474670100061 ()31252456 (PubMedID)2-s2.0-85068447779 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-04 (svasva)

Available from: 2019-07-04 Created: 2019-07-04 Last updated: 2023-09-05Bibliographically approved
de Melo, C., Jullien, M., Battie, Y., Naciri, A. E., Ghanbaja, J., Montaigne, F., . . . Horwat, D. (2019). Semi-Transparent p‑Cu2O/n-ZnO Nanoscale-Film Heterojunctions for Photodetection and Photovoltaic Applications. ACS Applied Nano Materials, 2(7), 4358-4366
Open this publication in new window or tab >>Semi-Transparent p‑Cu2O/n-ZnO Nanoscale-Film Heterojunctions for Photodetection and Photovoltaic Applications
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2019 (English)In: ACS Applied Nano Materials, ISSN 2574-0970, Vol. 2, no 7, p. 4358-4366Article in journal (Refereed) Published
Abstract [en]

Transparent nanoscale-film heterojunctions based on Cu2O and ZnO were fabricated by atomic layer deposition and reactive magnetron sputtering. The constitutive layers exhibit high crystalline quality and a local epitaxial relation between Cu2O and ZnO was achieved with [110] Cu2O || [001] ZnO and [001] Cu2O || [010] ZnO as evidenced by high resolution transmission electron microscopy and. Cu2O films show very low resistivity and high mobility values of 9–150 Ω cm and 19 cm2/V s, respectively. The Cu2O/ZnO heterojunctions exhibit a nonlinear rectifying behavior characteristic of a p–n junction, self-powered photoresponse under 1 Sun illumination and an average transmittance of 73% in the visible region of the electromagnetic spectrum. These results are promising for all-oxide transparent electronics, photodetection and photovoltaic applications.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
copper oxide, atomic layer deposition, local epitaxy, heterojunction, transparent electronics, photodetectors
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-75600 (URN)10.1021/acsanm.9b00808 (DOI)000477917700037 ()2-s2.0-85068417554 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-20 (johcin)

Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2023-09-05Bibliographically approved
Donarelli, M., Milan, R., Rigoni, F., Drera, G., Sangaletti, L., Ponzoni, A., . . . Comini, E. (2018). Anomalous gas sensing behaviors to reducing agents of hydrothermally grown α-Fe2O3 nanorods. Sensors and actuators. B, Chemical, 273, 1237-1245
Open this publication in new window or tab >>Anomalous gas sensing behaviors to reducing agents of hydrothermally grown α-Fe2O3 nanorods
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2018 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 273, p. 1237-1245Article in journal (Refereed) Published
Abstract [en]

α-Fe2O3 nanorods have been grown by hydrothermal method, dispersed in ethanol and drop casted on a pre-patterned alumina substrate with Pt electrodes. Their morphology, crystalline and electronic properties have been investigated by Scanning Electron Microscopy, Raman and X-ray Photoelectron Spectroscopies and X-ray Diffraction. The so-fabricated devices have been used for hydrogen gas sensing, showing their ability to detect H2 at operating temperatures > 200 °C, at relative humidity values comprised from 0% to 50%. The sensing behavior of α-Fe2O3 nanorods is compatible with an n to p conductivity transition when the operating temperature is increased up to 300 °C. Outstanding p-type hydrogen sensing performances of α-Fe2O3 have been observed and reported. Besides H2 detection, the α-Fe2O3 nanorods-based device is a good humidity sensor, at room temperature (n-type) and at 400 °C (p-type). CO and ethanol sensing performances have been investigated at different operating temperatures and relative humidity values. CO and ethanol anomalous acceptor-like behaviors at 200 °C in humid air has been explained by the interactions of these target gases with the water molecules adsorbed on the metal oxide surfaces. An explanation of the n–p behavior transition at T > 200 °C in terms of band bending is reported.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Hematite, n-p transition, Hydrothermal, Hydrogen sensing
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-70265 (URN)10.1016/j.snb.2018.07.042 (DOI)000441519000153 ()2-s2.0-85049771394 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-08 (andbra)

Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2021-03-31Bibliographically approved
De Melo, C., Jullien, M., Ghanbaja, J., Montaigne, F., Pierson, J.-F., Soldera, F., . . . Horwat, D. (2018). Local Structure and Point-Defect-Dependent Area-Selective Atomic Layer Deposition Approach for Facile Synthesis of p-Cu2O/n-ZnO Segmented Nanojunctions. ACS Applied Materials and Interfaces, 10(43), 37671-37678
Open this publication in new window or tab >>Local Structure and Point-Defect-Dependent Area-Selective Atomic Layer Deposition Approach for Facile Synthesis of p-Cu2O/n-ZnO Segmented Nanojunctions
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 43, p. 37671-37678Article in journal (Refereed) Published
Abstract [en]

Area-selective atomic layer deposition (AS-ALD) has attracted much attention in recent years due to the possibility of achieving accurate patterns in nanoscale features, which render this technique compatible with the continuous downscaling in nanoelectronic devices. The growth selectivity is achieved by starting from different materials and results (ideally) in localized growth of a single material. We propose here a new concept, more subtle and general, in which a property of the substrate is modulated to achieve localized growth of different materials. This concept is demonstrated by selective growth of high-quality metallic Cu and semiconducting Cu2O thin films, achieved by changing the type of majority point defects in the ZnO underneath film exposed to the reactive species using a patterned bilayer structure composed of highly conductive and highly resistive areas, as confirmed by transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The selective growth of these materials in a patterned ZnO/Al-doped ZnO substrate allows the fabrication of p-Cu2O/n-ZnO nanojunctions showing a nonlinear rectifying behavior typical of a p-n junction, as confirmed by conductive atomic force microscopy (C-AFM). This process expands the spectra of materials that can be grown in a selective manner by ALD and opens up the possibility of fabricating different architectures, taking advantage of the area-selective deposition. This offers a variety of opportunities in the field of transparent electronics, catalysis, and photovoltaics.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
area-selective deposition, atomic layer deposition, patterning, p−n junctions, transmission electron microscopy
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-71408 (URN)10.1021/acsami.8b12584 (DOI)000449239600118 ()30261135 (PubMedID)2-s2.0-85055202959 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-05 (johcin)

Available from: 2018-11-01 Created: 2018-11-01 Last updated: 2023-10-28Bibliographically approved
de Melo, C., Jullien, M., Battie, Y., En Naciri, A., Ghanbaja, J., Montaigne, F., . . . Horwat, D. (2018). Tunable Localized Surface Plasmon Resonance and Broadband Visible Photoresponse of Cu Nanoparticles/ZnO Surfaces. ACS Applied Materials and Interfaces, 10(47), 40958-40965
Open this publication in new window or tab >>Tunable Localized Surface Plasmon Resonance and Broadband Visible Photoresponse of Cu Nanoparticles/ZnO Surfaces
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 47, p. 40958-40965Article in journal (Refereed) Published
Abstract [en]

Plasmonic Cu nanoparticles (NP) were successfully deposited on ZnO substrates by atomic layer deposition (ALD) owing to the Volmer–Weber island growth mode. An evolution from Cu NP to continuous Cu films was observed with an increasing number of ALD cycles. Real and imaginary parts of the NP dielectric functions, determined by spectroscopic ellipsometry using an effective medium approach, evidence a localized surface plasmon resonance that can be tuned between the visible and near-infrared ranges by controlling the interparticle spacing and size of the NP. The resulting Cu NP/ZnO device shows an enhanced photoresponse under white light illumination with good responsivity values, fast response times, and stability under dark/light cycles. The significant photocurrent detected for this device is related to the hot-electron generation at the NP surface and injection into the conduction band of ZnO. The possibility of tuning the plasmon resonance together with the photoresponsivity of the device is promising in many applications related to photodetection, photonics, and photovoltaics.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
atomic layer deposition, copper nanoparticles, hot electrons, localized surface plasmon resonance, photodetectors
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-71637 (URN)10.1021/acsami.8b17194 (DOI)000451932800064 ()30398332 (PubMedID)2-s2.0-85056897869 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-12-04 (inah)

Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2023-10-28Bibliographically approved
Ghamgosar, P., Rigoni, F., You, S., Dobryden, I., Gilzad Kohan, M., Pellegrino, A. L., . . . Vomiero, A. (2018). ZnO-Cu2O core-shell nanowires as stable and fast response photodetectors. Nano Energy, 51, 308-316
Open this publication in new window or tab >>ZnO-Cu2O core-shell nanowires as stable and fast response photodetectors
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2018 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 51, p. 308-316Article in journal (Refereed) Published
Abstract [en]

In this work, we present all-oxide p-n junction core-shell nanowires (NWs) as fast and stable self-powered photodetectors. Hydrothermally grown n-type ZnO NWs were conformal covered by different thicknesses (up to 420 nm) of p-type copper oxide layers through metalorganic chemical vapor deposition (MOCVD). The ZnO NWs exhibit a single crystalline Wurtzite structure, preferentially grown along the [002] direction, and energy gap Eg=3.24 eV. Depending on the deposition temperature, the copper oxide shell exhibits either a crystalline cubic structure of pure Cu2O phase (MOCVD at 250 °C) or a cubic structure of Cu2O with the presence of CuO phase impurities (MOCVD at 300 °C), with energy gap of 2.48 eV. The electrical measurements indicate the formation of a p-n junction after the deposition of the copper oxide layer. The core-shell photodetectors present a photoresponsivity at 0 V bias voltage up to 7.7 µA/W and time response ≤0.09 s, the fastest ever reported for oxide photodetectors in the visible range, and among the fastest including photodetectors with response limited to the UV region. The bare ZnO NWs have slow photoresponsivity, without recovery after the end of photo-stimulation. The fast time response for the core-shell structures is due to the presence of the p-n junctions, which enables fast exciton separation and charge extraction. Additionally, the suitable electronic structure of the ZnO-Cu2O heterojunction enables self-powering of the device at 0 V bias voltage. These results represent a significant advancement in the development of low-cost, high efficiency and self-powered photodetectors, highlighting the need of fine tuning the morphology, composition and electronic properties of p-n junctions to maximize device performances.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
All-oxide NWs, Core-shell NWs, Self-powered photodetectors, Fast photodetectors, ZnO-Cu2O heterojunction
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-69838 (URN)10.1016/j.nanoen.2018.06.058 (DOI)000440682100034 ()2-s2.0-85049324019 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-02 (rokbeg)

Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2023-09-05Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7949-0935

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