High-κ Samarium-Based Metal-Organic Framework for Gate Dielectric Applications

The self-assembly of a samarium-based metal-organic framework [Sm₂(bhc)(H₂O)₆]_n (1) in good yield was achieved by reacting Sm(NO₃)₃·6H₂O with benzenehexacarboxylic acid (bhc) in a mixture of H₂O-EtOH under hydrothermal conditions. A structural analysis showed that compound 1 crystallized in a space group of Pnmn and adopted a 3D structure with (4,8) connected nets. Temperature dependent dielectric measurements showed that compound 1 behaves as a high dielectric material with a high dielectric constant (κ = 45.1) at 5 kHz and 310 K, which is comparable to the values for some of the most commonly available dielectric inorganic metal oxides such as Sm₂O₃, Ta₂O₅, HfO₂, and ZrO₂. In addition, electrical measurements of 1 revealed an electrical conductivity of about 2.15 × 10^-7 S/cm at a frequency of 5 kHz with a low leakage current (I_leakage = 8.13 × 10^-12 Amm^-2). Dielectric investigations of the Sm-based MOF provide an effective path for the development of high dielectric materials in the future.