Frequency-dependent dielectric behavior of aerosol jet-printed nanodiamond thin films

Direct write printing has been evolving rapidly as a viable technique to produce functional semiconducting, metallic and dielectric thin films on rigid and flexible substrates. Diamond thin films produced by conventional epitaxial techniques have found a wide range of applications, and printing has the potential to provide functional diamond thin films inexpensively and over large areas. Here, the frequency-dependent electrical behavior of printed nanodiamond thin films is investigated to clarify their charge-transport and dielectric characteristics. Detonation nanodiamond inks were printed into continuous films by aerosol jet printing. The structural and chemical properties were evaluated through transmission electron microscopy, Raman spectroscopy, and additional thermal and surface analysis. Electrical characterization over a broad frequency range revealed predominantly capacitive behavior with impedance decreasing as annealing temperature increased. Capacitance-frequency measurements showed a stable mid-frequency dielectric response, while thermal activation analysis indicated that the transport is dominated by trap-assisted or interfacial conduction mechanisms. These findings establish aerosol-jet printed nanodiamond films as high-resistivity dielectric layers whose electrical properties evolve predictably with annealing temperature and frequency, supporting their potential use in flexible electronics, insulating layers, and high temperature sensing platforms.