Alternating current conduction properties of thermally evaporated α-nickel phthalocyanine thin films: Effects of oxygen doping and thermal annealing | Zendy

Thomas D. Anthopoulos | Zendy; T.S. Shafai | Zendy

Open Access

Alternating current conduction properties of thermally evaporated α-nickel phthalocyanine thin films: Effects of oxygen doping and thermal annealing

Author(s) -

Thomas D. Anthopoulos,

T.S. Shafai

Publication year - 2003

Publication title -

journal of applied physics

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.699

H-Index - 319

eISSN - 1089-7550

pISSN - 0021-8979

DOI - 10.1063/1.1592626

Subject(s) - materials science , annealing (glass) , doping , thermal conduction , dissipation factor , nickel , analytical chemistry (journal) , ohmic contact , conductivity , thin film , atmospheric temperature range , phthalocyanine , capacitance , electrical resistivity and conductivity , oxygen , electrode , chemistry , optoelectronics , composite material , metallurgy , dielectric , nanotechnology , physics , engineering , chromatography , layer (electronics) , meteorology , electrical engineering , organic chemistry

The ac conduction properties of thermally evaporated films of α-nickel phthalocyanine (α-NiPc) were studied in situ and ex situ employing symmetric gold ohmic electrodes in the frequency range of 20−106 Hz at various temperature regimes. ac conductivity was identified to be via a hopping-type mechanism in the lower temperature region and via a free-band conduction in the high temperature region. Upon exposure of the films to dry air, the low frequency ac conductivity was found to increase by 2 orders of magnitude, which was attributed to oxygen absorption within NiPc. The doping effect was partially reversed by thermal annealing of the films under high vacuum. Measurements on the dependence of capacitance and loss tangent (tanδ) on frequency were consistent and quantitatively explained by invoking an equivalent circuit model. Oxygen doping was found to increase the low frequency capacitance of NiPc. The phenomenon was understood in terms of reduction in the value of device internal resistance induced by o...

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