Abstract
Vacuum evaporated thin films of aluminium phthalocyanine hydroxide were prepared at room temperature onto glass
substrates at a base pressure of 10-5 torr. Annealing was done in air and the effect of annealing temperature on the
electrical, optical and structural properties were studied. Arrhenius plot yields thermal activation energy in the intrinsic region and impurity scattering region. Optical absorption spectra of films annealed at temperatures 348 K, 398 K and 448 K were taken over a wavelength range of 350 to 900 nm and the optical energy band gap Eg and the onset energy gap were calculated. Refractive index n, extinction coefficient k and the real and imaginary parts of the optical dielectric constant ε1 and ε2 were also evaluated and were plotted against the photon energy. Photoluminescence (PL) spectrum was investigated to identify impurity levels and to gauge disorder and interface roughness. Scanning electron microscope (SEM) images were taken to study the surface morphology of the film. X-ray diffraction pattern was used to find the nanocrystalline grain size using Scherrer formula. An increase in grain size with annealing temperature was observed..
Keywords
Thin film, Activation energy, Refractive index, Optical band gap.
Citation
SUSAN MATHEW, C. SUDARSANAKUMAR, C. S. MENON, Spectral, thermal and structural studies on aluminium phthalocyanine hydroxide thin films, Optoelectronics and Advanced Materials - Rapid Communications, 4, 1, January 2010, pp.63-69 (2010).
Submitted at: Jan. 3, 2009
Accepted at: Jan. 19, 2010