Effects of Yb, Mn and Au transparent metal substrates on the structural and optical properties of phthalocyanine (ZnPC) thin films رسالة ماجستير

Abstract

In this thesis, we attempted to alter the structural, optical and dielectric properties of ZnPC thin films through establishing a transparent metal surface that interacts with the organic material pthalocyanine (ZnPC) to form Plasmon-electron interacting media. For this purpose, the ZnPC thin films are coated onto glass, Yb, Au and Mn substrates of 150 nm thicknesses. The films are structurally, morphologically and optically analyzed. It was observed that while the Mn and Au substrates forces amorphous nature of growth of ZnPC films, the glass and Yb caused the growth of monoclinic phase of pthalocyanine. The Yb substrate increased the crystallite size and decreased the micro strain, dislocation density and stacking faults. Optically, ZnPC films exhibit strong absorption bands in the high and low energy range of spectrum. It is observed that while Mn substrate motivated the formation of wide band tails, Au and Yb formed narrower band tails. One result that is worthy of consideration is that the Mn substrate successfully increased the light absorbability by 21 times compared to Au and Yb substrates which increased the light absorbability by five and three times near 2.5 eV, respectively. Estimations of the effects of the metal substrates on the energy band gap have shown that these metals don’t strongly affect the energy band gap. On the other hand, while the dielectric response at high frequency is not affected by the presence of metals, the dielectric spectra in the infrared range is enhanced by 37.3%, 57.5%% and 181.95% when ZnPC was coated onto Yb, Mn and Au substrates, respectively, near l.l10 eV. The modeling of the imaginary part of the dielectric spectra assuming the validity of Drude -Lorentz model has shown that the metal substrates improves the drift mobility from 0.46 to 7.49, 6.86 and 7.50 cm?/Vs when films were coated onto Yb, Au and Mn. While the Yb substrates decreased the Plasmon frequency, the Au and Mn substrates highly increased it to levels that make it more appropriate for optoelectronic technology applications.