Morphology, structural and optical characterization of electron beam evaporated bromoaluminium phthalocyanine (BrAlPc) thin films

Bromoaluminium phthalocyanine (BrAlPc) thin films have been deposited onto pre-cleaned glass substrates by electron beam evaporation technique. Thin films have been characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and optical absorption (UV–Vis) spectra. XRD studies of BrAlPc thin film deposited at room temperature shows the indication of the α-phase. FESEM images have shown that the most of particles are spherical in shape with an average size about 26–34 nm. Using UV–Visible spectra over the wavelength range 300–800 nm, the optical band gap, absorption coefficient and extinction coefficient of BrAlPc thin films are evaluated. The optical absorption measurements of thin films show that the absorption mechanism is due to direct transition.     

Influence of temperature and frequency on electrical properties of electron beam evaporated bromoaluminum phthalocyanine, BrAlPc, thin films

The AC electrical properties of electron beam evaporated Bromoaluminum phthalocyanine (BrAlPc) thin films have been studied in the frequency range 10²–10⁵ Hz and in the temperature range of 303–413 K. The BrAlPc thin films are characterized by field emission scanning electron microscopy (FESEM). The capacitance is found to be sensitive to the frequency and increases with increasing temperature and decreases with increasing frequency. A loss minimum has been observed in the frequency dependence of the dissipation factor. Such behavior is found to be in good qualitative agreement with the model of Goswami and Goswami. The AC conductivity $\sigma \left( \omega \right)$ σ ( ω ) is found to vary as $\omega^{s}$ ω s in the studied frequency range. At frequencies 10–10² Hz, s is less than unity and decreases with increase in temperature indicating a dominant hopping process. At frequency ranges 10²–10⁴ Hz, exponent s lies very close to the unity and is independent of temperature, which shows the quantum mechanical tunneling is dominated conduction mechanism. At higher frequencies 10⁴–10⁵ Hz, s is found to be temperature independent. The temperature dependence of AC conductivity shows a linear increase with the increase in temperature. Moreover, the activation energies of device are determined as a function of frequency.     

Synthesis, morphology and optical properties of nanocomposite thin films based on polypyrrole-bromo-aluminium phthalocyanine

This paper is focused on the synthesis of nanocomposite Polypyrrole–Bromoaluminium phthalocyanine (PPy-BrAlPc). Morphology of prepared nano-compositethin films by electron beam evaporation technique have been well characterized by Field Emission-Scanning Electron Microscopy (FESEM). FESEM shows that the grain sizes are increased with increase in concentration of pyrrole. The optical properties of nanocomposite thin films have been investigated using a spectrophotometric measurement of absorbance in the wavelength range 300–800 nm. Absorption spectra of the films show B-band in the UV region followed by Q-band in the visible region. Moreover, the optical band gaps of the thin films are evaluated. It is found that the energy of the optical band gap increases as the concentration of Bromo-aluminium phthalocyanine increases.     

Investigation of morphology, a.c. electrical and optical properties of nanostructured thin film of polypyrrole–bromoaluminium phthalocyanine

In this research, nanocomposite polypyrrole (PPy) + 30 % bromoaluminium phthalocyanine (BrAlPc) was prepared in our laboratory. Optical absorption and field emission scanning electron microscopy characterized the thin films. The powder of nanocomposite was characterized by X-ray diffraction. The nanocomposite PPy + 30 % BrAlPc thin film deposited on pre-cleaned glass substrate with a thickness of 100 nm, which was deposited in a high vacuum device of electron-beam gun in the pressure of 10^?5 mbar. The capacitance and the dissipation factor were measured in a.c. electrical and in the range of 10²–10⁵ Hz frequency and 303–413 K temperatures. The nanoparticles are spherical in shape with an average size about 25–37 nm. Their UV–Vis spectra of the nanocomposite (PPy + 30 % BrAlPc) is typically described by two strong Q and Soret bands 600–700 and 300–400 nm. The results showed a sharp diffraction peak appeared in 2θ = 8.72 (d = 10.1296 Å) and grian size D = 8.991 nm. The results can be described by the theory of Goswami–Goswami for sandwich devices.     

Effects of post-deposition annealing on morphology and optical properties of electron beam evaporated Bromoaluminium phthalocyanine thin films

In this paper, effects of post-deposition annealing on morphology and optical properties of electron beam evaporated Bromoaluminium phthalocyanine thin films have been investigated. Surface morphology of the films have been characterized by field emission scanning electron microscopy (FESEM). The FESEM micrographs have shown densely packed nanoparticles and nanorod-like structures for the films annealed at different temperatures. Conditions leading to β-phase have been identified by monitoring post-deposition annealing using optical absorption spectroscopy (UV–Vis). The optical absorption measurements on the as-deposited and annealed films shows that the absorption mechanism is due to direct transition. Also, it is found that the optical band gap decreases with increase in annealing temperature.     

Optical characterization of organic material bromoindium phthalocyanine thin films grown by electron beam evaporation

This paper presents the optical properties of organic material bromoindium phthalocyanine (BrInPc) thin films grown by electron beam evaporation technique. The paper describes the optical characteristics of BrInPc thin films, which have been determined using spectrophotometric measurements of the absorbance, transmittance and reflectance at normal incident of light in the spectral range 300–1,100 nm. The optical band gap energy and type of the electronic transition have been determined by analysis of spectral behavior of absorption coefficient, which reveals the probability of both direct and indirect transitions. Other optical constants, such as refractive index, extinction coefficient, complex dielectric constant and optical conductivity of thin films have been evaluated. Moreover, the width of band tails of localized states (Urbach energy), steepness parameter and width of the defect states have been determined by studying the absorption coefficient spectra just below the fundamental absorption edge.