Pulsed laser deposition and characterization of ZnO nanopores
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Pulsed laser deposition and characterization of ZnO nanopores Poulami Ghosh1 • Ashwini K. Sharma1
Received: 23 February 2015 / Accepted: 10 November 2015 Ó Springer-Verlag Berlin Heidelberg 2016
Abstract We report on the deposition and characterization of ZnO nanopore structures by pulsed laser deposition technique at a fixed substrate temperature and at different deposition times on a silicon (100) substrate. X-ray diffraction shows that ZnO nanopore structures are highly oriented along c-axis. Morphological analysis of the nanostructures studied by FESEM and AFM confirms the pores nature of the structures. The morphological evolution of the nanostructures as a function of deposition time is discussed on the basis of Stranski–Krastanov growth model. Optical properties of the nanostructures studied by photoluminescence spectra indicate that the observed transitions are from near band edge as well as from defectrelated states.
1 Introduction A variety of one-dimensional (1D) ZnO nanostructures have been reported in the literature, such as nanotubes, nanosheets, nanobelts, nanowires, owing to some interesting applications such as gas sensor [1], solar cell [2], nanogenerators, Schottky diodes, light-emitting devices [3]. Nanowalls are two-dimensional (2D) novel nanostructures that can potentially be used for optoelectronics and in sensor devices due to their large surface area, diverse shape and easy manipulation for device applications and have the potential for applications in sensors [4], energy storage devices, solar cell [2]. In recent years, 2D & Ashwini K. Sharma [email protected] 1
Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam, India
nanostructures of ZnO and its composites such as ZnO nanowall networks and composite structures have been synthesized by various methods with or without using catalysts. Vertically well-aligned ZnO nanowall networks on GaN layer/Al2O3 substrates were grown with the help of Au catalyst and nanowall network structures had shown H2 sensing properties [5]. ZnO nanowalls were achieved at high temperature of 900 °C for a longer time (90 min) by mixing of ZnO and graphite powder (1:1) in argon atmosphere [5]. ZnO nanowalls were grown by MOCVD process without using any catalyst, and they have shown that the nanowall density gets increased with the increase in deposition time [6]. ZnO nanowall network structures were grown by vapor-phase transport process and showed luminescence by forming whispering gallery cavity mode from the nanowall structures [7]. ZnO nanowall network structures have been synthesized by various approaches like plasma-assisted molecular beam epitaxy [8] and hydrothermal method [9] grown on silicon (111) and sapphire substrates, respectively. Several nanostructures are porous/pores in nature synthesized by several deposition techniques and materials reported in the literature like porous structures (flower-like hollow microspheres of ZnIn2S4) synthesized by biomolecular-assisted synthesis [10], porous zinc ferrite films synt
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