Controlled performance of an organic transistor memory device with an ultrathin LiF blocking layer

Abstract

In this paper, the controlled performance of a novel organic pentacene transistor memory device with an ultrathin LiF blocking layer was investigated. Our results demonstrate the introduction of an ultrathin LiF layer has a significant influence on the transistor memory performance. As the LiF thickness increased from 0 to 3 nm, the charge carrier mobility showed a three-fold increase from 0.15 to 0.43 cm² V⁻¹ s⁻¹ due to hole injection enhancement. Moreover, the on/off current ratio increased from 5 to 50 at long measurement times. This significant enhancement of charge retention behavior (∼10 times improvement) was ascribed to the LiF blocking effect when the trapped charge was released from silver nanoparticle induced trap centers. However, the memory window showed a slight decrease from 60 to 37 V, which is due to the decreased penetration depth of silver nanoparticles into the pentacene layer. The physical origin of the memory effect with the LiF ultrathin layer was also discussed. Our introduction of an ultrathin LiF layer offers a simple and feasible way to control the different memory performances of this novel transistor memory device.