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Title: Effect of annealing on the growth dynamics of ZnPc LB thin film and its surface morphology

The ZnPc molecules in the thin film prepared by Langmuir-Blodgett (LB) process in asdeposited state has been found to have an edge on orientation with average tilt angle of 64.3 ° as confirmed from the Pressure-Area (π-A) isotherm and X-ray diffraction (XRD) study. The ZnPc LB thin film has been observed to have abnormal growth mode at higher annealing temperature and it is mainly driven by minimization of surface free energy which lead to large increase in crystallinity of the film. Kinetically favored orientational and structural transitions of ZnPc thin film during annealing and their effect on the surface morphology of the thin film has been studied using scaling concepts. The scaling exponents 1) root mean square (RMS) roughness σ, 2) roughness exponent α and, 3) in plane correlation length ξ are calculated from the HDCF g(r) and ACF C(r). The RMS surface roughness σ is found to be dependent on the as defined short wavelength undulations (ρ) and long wavelength undulations (χ). Both ρ and χ are the function of all the three scaling exponents. σ has been observed to be maximum for the ZnPc thin film annealed at 290 °C, since the χ shoot to maximum value at this temperaturemore » due to the formation of small domains of ZnPc nanorods. The self affinity of the ZnPc thin film is found to decrease on annealing as obtained from both power spectral density (PSD) and HDCF g(R) and ACF C(R) study, which confirms that the dimension of surface morphology of the ZnPc LB thin film transform towards 2D with increase in annealing temperature.« less
Authors:
; ;  [1]
  1. Nanoscience and Thin Film Laboratory, Department of Applied Physics, Indian School of Mines, Dhanbad 826004, India. (India)
Publication Date:
OSTI Identifier:
22299779
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 7; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; FREE ENERGY; ISOTHERMS; NANOSTRUCTURES; SPECTRAL DENSITY; THIN FILMS; WAVELENGTHS; X-RAY DIFFRACTION