Capacitance characteristics of MOS capacitors embedded with colloidally synthesized gold nanoparticles

In this work, the capacitance characteristics of gold nanoparticle-embedded metal-oxide-semiconductor (MOS) capacitors with Al₂O₃ control oxide layers are investigated. The capacitance versus voltage (C-V) curves obtained for a representative MOS capacitor embedded with gold nanoparticles synthesized by the colloidal method exhibit large flat-band voltage shifts, which indicate the presence of charge storages in the gold nanoparticles. Their hysteresis characteristics are dependent on the voltage sweep range. The clockwise hysteresis and rightward shift of the flat band voltages observed from the C-V curves imply that electrons are trapped in a floating gate layer consisting of the gold nanoparticles present between SiO₂ and Al₂O₃ layers in the MOS capacitor, and that these trapped electrons originate from the top electrode. In addition, the characteristics of the capacitance versus time curves for the gold nanoparticle-embedded MOS capacitor are discussed in this paper.