Effect of Al 3+ /Si 4+ codoping on the structural, optoelectronic and UV sensing properties of ZnO
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Effect of Al3+/Si4+ codoping on the structural, optoelectronic and UV sensing properties of ZnO Saniya Ayaz1, Neha Sharma2, Aditya Dash3, Somaditya Sen4,5,a) 1
Metallurgical Engineering and Material Science, Indian Institute of Technology, Indore 453552, India Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Sonepat, Haryana 131039, India 3 Department of Physics and Astronomy, National Institute of Technology Rourkela, Odisha, 769008, India 4 Discipline of Physics, Indian Institute of Technology Indore, Indore 453552, India 5 Electronic Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan. a) Address all correspondence to this author. e-mail: [email protected] 2
Received: 25 December 2019; accepted: 26 March 2020
The structural, vibrational, and optoelectronic properties of sol–gel synthesized Zn1−x(Al0.5Si0.5)xO nanoparticles were investigated. The X-ray diffraction studies of the samples confirmed the hexagonal wurtzite phase with the space group P63mc. No significant changes were observed in the lattice parameters. The increase in the 2 Raman mode observed at 438 cm−1 indicates a decrease in the crystallite size. The reduction in intensity of Ehigh the deep-level emission band with the introduction of Al/Si indicates a decrease in intrinsic defects for the codoped sample. A unique electron paramagnetic resonance signal at g = 1.96 follows the same trend as the green luminescence, and its evolution was shown to probe the oxygen vacancy concentrations. I–V characteristics curve confirm the increase in the conductivity for the codoped samples. To evaluate the role of surface defects, ultraviolet photoresponse behavior as a function of time was also studied, and an increase in the photocurrent was observed. The slow decay and rise in the photocurrent are because of multiple trapping by interstitial defects. A relatively faster response time was observed with the substitution of Al/Si. It has been observed that prepared nanomaterials are suitable for optoelectronic devices.
Introduction Zinc oxide (ZnO) is a semiconductor with the energy band gap of 3.37 eV at room temperature and a relatively high exciton binding energy of 60 meV than GaN [1]. It has gained a great
for photosensitive devices to operate in the UV-visible to near-infrared region (NIR), especially for enhanced UV photodetection and white LEDs. Massive light absorption in the UV region due to the large band gap, large surface to volume ratio,
deal of attention because of its potential applications in
prominent UV and visible photoluminescence (PL), and fast
optoelectronics as ultraviolet (UV) absorbers [2], light-emitting
photocurrent responses in ZnO make it suitable for photocon-
diode (LED) materials [3], field-effect transistors (FETs) [4],
ductive applications [2, 9]. For example, the optoelectronic properties of ZnO can be greatly enhanced by doping with group III elements such as
and spintronic devices [5]. However, ZnO is insensitive to visible light because of its wide band gap, a
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