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Synthesis and Characterization of Nanostructured Multi-Layer Cr/SnO 2/NiO/Cr Coatings Prepared via E-Beam Evaporation Technique for Metal-Insulator-Insulator-Metal Diodes. MATERIALS 2022; 15:ma15113906. [PMID: 35683204 PMCID: PMC9182535 DOI: 10.3390/ma15113906] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 12/10/2022]
Abstract
Enhanced non-linearity and asymmetric behavior of the Cr/metal oxide diode is reported, with the addition of two insulator layers of SnO2 and NiO to form the metal-insulator-insulator-metal (MIIM) configuration. Such an MIIM diode shows potential for various applications (rectifiers and electronic equipment) which enable the femtosecond fast intoxication in MIIM diodes. In this work, nanostructured multi-layer Cr/SnO2/NiO/Cr coatings were fabricated via e-beam evaporation with the following thicknesses: 150 nm/20 nm/10 nm/150 nm. Coatings were characterized via Rutherford backscattering (RBS), scanning electron microscopy (SEM), and two-probe conductivity testing. RBS confirmed the layered structure and optimal stoichiometry of the coatings. A non-linear and asymmetric behavior at <1.5 V applied bias with the non-linearity maximum of 2.6 V−1 and the maximum sensitivity of 9.0 V−1 at the DC bias point was observed. The promising performance of the coating is due to two insulating layers which enables resonant tunneling and/or step-tunneling. Based on the properties, the present multi-layer coatings can be employed for MIIM application.
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Rehman I, Hanif MB, Alghamdi AS, Khaliq A, Halim KSA, Subhani T, Motola M, Khan AF. Intrinsic Properties of Multi-Layer TiO 2/V 2O 5/TiO 2 Coatings Prepared via E-Beam Evaporation. MATERIALS 2022; 15:ma15113933. [PMID: 35683236 PMCID: PMC9182047 DOI: 10.3390/ma15113933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/20/2022] [Accepted: 05/29/2022] [Indexed: 11/16/2022]
Abstract
Nanocomposite multi-layer TiO2/V2O5/TiO2 thin films were prepared via electron-beam evaporation using high-purity targets (TiO2 and V2O5 purity > 99.9%) at substrate temperatures of 270 °C (TiO2) and 25 °C (V2O5) under a partial pressure of oxygen of 2 × 10−4 mbar to maintain the stoichiometry. Rutherford backscattering spectrometry was used to confirm the layer structure and the optimal stoichiometry of the thin films, with a particle size of 20 to 40 nm. The thin films showed an optical transmittance of ~78% in the visible region and a reflectance of ~90% in the infrared. A decrease in transmittance was observed due to the greater cumulative thickness of the three layers and multiple reflections at the interface of the layers. The optical bandgap of the TiO2 mono-layer was ~3.49 eV, whereas that of the multi-layer TiO2/V2O5/TiO2 reached ~3.51 eV. The increase in the optical bandgap was due to the inter-diffusion of the layers at an elevated substrate temperature during the deposition. The intrinsic, structural, and morphological features of the TiO2/V2O5/TiO2 thin films suggest their efficient use as a solar water heater system.
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Affiliation(s)
- Irfa Rehman
- Department of Materials Science and Engineering, Institute of Space Technology, 1-National Highway, Islamabad 44000, Pakistan;
| | - Muhammad Bilal Hanif
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, Mlynska Dolina, 842 15 Bratislava, Slovakia;
| | - Abdulaziz Salem Alghamdi
- College of Engineering, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia; (A.S.A.); (A.K.); (K.S.A.H.)
| | - Abdul Khaliq
- College of Engineering, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia; (A.S.A.); (A.K.); (K.S.A.H.)
| | - K. S. Abdel Halim
- College of Engineering, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia; (A.S.A.); (A.K.); (K.S.A.H.)
- Central Metallurgical Research and Development Institute (CMRDI), P.O. Box 87, Helwan 11421, Egypt
| | - Tayyab Subhani
- College of Engineering, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia; (A.S.A.); (A.K.); (K.S.A.H.)
- Correspondence: (T.S.); (M.M.); or (A.F.K.)
| | - Martin Motola
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovicova 6, Mlynska Dolina, 842 15 Bratislava, Slovakia;
- Correspondence: (T.S.); (M.M.); or (A.F.K.)
| | - Abdul Faheem Khan
- Department of Materials Science and Engineering, Institute of Space Technology, 1-National Highway, Islamabad 44000, Pakistan;
- Correspondence: (T.S.); (M.M.); or (A.F.K.)
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