https://doi.org/10.1140/epjp/s13360-023-04244-2
Regular Article
Negative photoconductivity: optical and structural characterization of PVP encapsulated CuO nanorods for the study of negative photoconductivity effect
1
Department of Physics, Government General Degree College Gopiballavpur-II, 721517, Jhargram, India
2
Department of Microelectronics and VLSI Technology, Maulana Abul Kalam Azad University of Technology, 741249, Haringhata, India
3
Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology Kharagpur, 721302, Paschim Medinipur, India
4
School of Nano Science and Technology, Indian Institute of Technology Kharagpur, 721302, Paschim Medinipur, India
5
Department of Physics, Vidyasagar University, 721102, Paschim Medinipur, West Bengal, India
Received:
27
February
2023
Accepted:
30
June
2023
Published online:
14
July
2023
In this report, the optical and structural properties of the PVP incorporated CuO naorods (NRs) have been studied and discussed for the observation of the photoconductivity response. The band gap of the CuO NRs was found to be ≈ 3.85 eV with UV and visible emission (violet and blue light) properties related to the defects and interstitial formation in the NRs. The observed quantum yield of blue higher emission around 487 nm is stronger than other emitted colors from the CuO NRs. Optical refractive index, susceptibility, and optical dielectric constant, conductivity, optical dispersion parameters have been studied from optical spectrum.The crystal phase from the XRD result showed a monoclinic nature with an average crystal size ≈12.5 nm, strain ≈0.002 and lattice parameters: a = 4.5578 Å, b = 3.5474 Å, c = 5.2911 Å. Formation of the pure phase of CuO and presence of different vibrational bond (such as the Cu–O stretching vibration along the [101] direction at 604.5 cm−1) have been observed from FTIR spectrum. The current–voltage characteristics of the polymer encapsulated CuO NRs deposited on the glass substance have been investigated after exposure to UV light. The maximum current under dark and UV illumination were 4μA and 0.075μ A at 2 V, respectively. The carrier relaxation under UV irradiation showed negative photoconductivity (NPC) response with different relaxation time. The photoconductivity rise and decay showed the raise time t1 = 1193 s, t2 = 1050 s and decay time τ1 = 935 s, τ2 = 188 s. The decay current under UV light showed the involvement of carrier relaxation by the trapping process as well as recombination process. The carrier dynamics and NPC study in the PVP encapsulated CuO NRs is useful for the future optoelectronic devices.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
