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Effect of 120 MeV Au 9+ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction
Author(s) -
Das Pankaj Kumar,
Biswal Rajib,
Choudhary Ram Janay,
Sathe Vasant,
Ganesan Vedachalaiyer,
Khan Saif Ahmad,
Mishra Naresh Chandra,
Mallick Pravanjan
Publication year - 2018
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6512
Subject(s) - materials science , fluence , irradiation , non blocking i/o , raman spectroscopy , analytical chemistry (journal) , ion , heterojunction , surface roughness , thin film , optics , composite material , nanotechnology , optoelectronics , chemistry , biochemistry , physics , organic chemistry , chromatography , nuclear physics , catalysis
ZnO/NiO thin films, each of thickness 100 nm, were deposited on Si(100) substrate by pulsed laser deposition method. The resulting heterojunction, ZnO/NiO/Si, was irradiated by 120 MeV Au 9+ ions and characterized by grazing incidence X‐ray diffraction (GIXRD), Raman spectroscopy, and atomic force microscopy (AFM). The GIXRD confirmed the presence of both NiO and ZnO in the samples. Ion irradiation induced suppression of crystalline nature, and the recrystallization of the same occurred at the fluence of 1 × 10 13 ions cm −2 . The occurrence of most intense band at 302 cm −1 in Raman spectra corresponds to the symmetric stretching vibration of ZnO. The linear shift of stretching mode of ZnO with ion fluence could be associated with the effect of compressive stress in the material. AFM analysis of the films indicated that the rms roughness increased when the film is irradiated at a fluence of 1 × 10 12 ions cm −2 . Beyond this fluence, the value of roughness decreased up to fluence of 1 × 10 13 ions cm −2 and increased thereafter. To see the effect of the stress of buffer layer on the surface layer, we calculated the stress for NiO layer with ion fluence form the lattice parameter. Comparing the stress of buffer layer with roughness of surface layer at the given fluence, we can say that the compressive stress in the buffer layer could possibly control the roughness of the surface layer.