The effects of thermal power and deposition time on the structural characteristics of ZnO nanorods and their optical pro
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The effects of thermal power and deposition time on the structural characteristics of ZnO nanorods and their optical properties for photovoltaic applications S. Nasih1 · A. Dloo1 · G. El Hallani2 · N. Fazouan1 · E. H. Atmani1 · A. Liba2 Received: 15 February 2020 / Accepted: 18 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this study, zinc oxide nanowires are elaborated by the hydrothermal method using a microwave furnace, which varies power and deposition times. The growth of nanowires is done on a buffer layer deposited on glass substrates using the sol–gel method associated with spin-coating. The X-Ray Diffraction (XRD) spectrums indicate that the obtained nanowires are well oriented in (002) plane according to the hexagonal wurtzite phase. The density and length of these nanowires increase while their diameter decreases with the deposition time and the microwave power. For high powers and longer deposition times, the ZnO nanowires adopt a pyramidal shape due to the low concentration of O H− hydroxides in the deposition solution. The elaborated nanowires have an optical transmittance level in the visible region of about 90% with a red shift of the optical gap as the deposition time increases qualifying them for photovoltaic and other optoelectronic applications. A correlation between the diameter of the nanowires and their optical gap has been found which illustrates the narrow relationship between the structural, electronic, and optical aspects of these nanowires. Keywords ZnO nanowires · Hydrothermal technique · Power furnace · Time deposition · Structural and optical correlation · Photovoltaic application
1 Introduction In recent years, there was immense interest in semiconductor nanostructures due to their unique optoelectronic properties [1–5]. Among these nanostructures, ZnO is one of the most promising materials due to its direct bandwidth of 3.3 eV and high excitonic binding energy of 60 meV [6]. ZnObased nanostructures have a wide range of applications; it can be used in light-emitting diodes (LEDs) [7], UV nanolasers [8], field-effect transistors [9], solar cell electrodes [10, 11] and nanogenerators [12]. In all these applications, one of the main objectives is to control the morphology, size, and * N. Fazouan [email protected] 1
Laboratory of Physics of Condensed Matters and Renewables Energies, Hassan II University, Faculty of Sciences and Technologies, B.P 146, 20650 Mohammedia, Morocco
Laboratory of Materials Physics, Sultan Moulay Slimane University, Faculty of Sciences and Technologies, B.P 523, 23000 Beni Mellal, Morocco
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density of ZnO nanowires as these parameters have a major impact on the electronic and optical properties of ZnO. Many deposition methods were used to develop ZnO nanowires, including vapor–liquid-solid (VLS) [13, 14], chemical vapor deposition (CVD) [15, 16] and metal–organic chemical vapor deposition (MOCVD) [17, 18]. Most of these deposition techniques are expensive and require special high-temperature treatment. However
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