Nanoparticle size dependent threshold voltage shifts in organic memory transistors

The performance of organic field-effect transistor (OFET) memory devices with different size of gold nanoparticles (Au NPs) as charge trapping layers has been investigated. We synthesized 15 nm, 20 nm and 25 nm of Au NPs through a citrate-reduction method and 3-aminopropyltriethoxysilane (APTES) functionalized substrates were used to form a monolayer of Au NPs. In the programming/erasing operation, we observed reversible threshold voltage (V(th)) shifts and reliable memory performances. A strong size-dependent effect on V(th) shifts and memory effect was observed. Effect of size dependence on the mobilities (mu), on/off current ratios, subthreshold swings (S), data retention characteristics (>10(5) s) and endurance performances operation (>800 cycles) of memory devices are discussed. The experimental results suggest a guideline for optimizing the size and density of Au NPs and their influence on the device properties.