Dielectric response and electric properties of organic semiconducting phthalocyanine thin films

作     者：A.M.Saleh S.M.Hraibat R.M-L.Kitaneh M.M.Abu-Samreh S.M.Musameh 

作者机构：Physics DepartmentAl-Quds UniversityJerusalemPalestine physics DepartmentAn-Najah UniversityNablusPalestine 

出 版 物：《Journal of Semiconductors》 (半导体学报（英文版）)

年 卷 期：2012年第33卷第8期

页      面：15-21页

核心收录：

学科分类：080903[工学-微电子学与固体电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

主　　题：organic semiconductor dielectric function evaporation relaxation time 

摘      要：The dielectric function of some phthalocyanine compounds （ZnPc, H2Pc, CuPc, and FePc） were investigated by analyzing the measured capacitance and loss tangent data. The real part of the dielectric constant, ca, varies strongly with frequency and temperature. The frequency dependence was expressed as： ε1 = Aε^n, where the index, n, assumes negative values （n 〈 0）. In addition, the imaginary part of the dielectric constant, ε2, is also frequency and temperature dependent. Data analysis confirmed that ε2 = Bo）m with values of m less than zero. At low frequencies and all temperatures, a strong dependence is observed, while at higher frequencies, a moderate dependence is obvious especially for the Au-electrode sample. Qualitatively, the type of electrode material had little effect on the behavior of the dielectric constant but did affect its value. Analysis of the AC conductivity dependence on frequency at different temperatures indicated that the correlated barrier hopping （CBH） model is the most suitable mechanism for the AC conduction behavior. Maximum barrier height, W, has been estimated for ZnPc with different electrode materials （Au and AI）, and had values between 0.10 and 0.9 eV. For both electrode types, the maximum barrier height has strong frequency dependence at high frequency and low temperatures. The relaxation time, r, for ZnPc and FePc films increases with decreasing frequency. The activation energy was derived from the slopes of r versus 1/T curves. At low temperatures, an activation energy value of about 0.01 eV and 0.04 eV was estimated for ZnPc and FePc, respectively. The low values of activation energy suggest that the hopping of charge carriers between localized states is the dominant mechanism.