Size and Temperature Effect on Electrical Conductivity, Dielectric Properties, and Electrical Switching Memory Application of Nanocrystalline Na-DDQ (Metal-Organic Frameworks) Thin Films

Abstract

Organometallic Sodium-2,3-Dichloro-5,6-dicyano-p-benzoquinone (Na-DDQ) films were synthesized using a conventional thermal vacuum deposition technique at ambient temperature. DC electrical resistivity was measured over a wide range of thicknesses and temperatures. This helps in investigating the different size-effect parameters, for instance the bulk mean free path (λ o ), bulk resistivity (ρ o ), grain-boundary transmission coefficient (t), surface scattering factor (p), external surface parameters (U), and grain-boundary parameter (V) in specular and non-specular conditions. The contribution of grain-boundary and surface resistivity to total resistivity was then estimated. Additionally, the AC conductivity (σ ac ) and dielectric (ε) behavior of Na-DDQ films were examined at the same temperature in the frequency range (50 Hz-5 MHz). Thus, the temperature dependence of frequency exponent factor (s) was calculated and interpreted in terms of various conduction models. The AC activation energy and its frequency dependence were extracted. The dielectric properties were attributed using electric modulus and complex permittivity of the studied films. Finally, Na-DDQ films showed a memory and switching behavior during the I–V characterization, the On-Off states were observed by applying an external electric field. Hence, the switching parameters for instance threshold voltage (Vth), switching time (τ s) and delay time (τ d) of samples were evaluated.