Bipolar resistive switching and nonvolatile memory effect in poly (3-hexylthiophene) –carbon nanotube composite films

Abstract

The resistive switching behavior and nonvolatile memory effects have been investigated in poly (3-hexylthiophene) (P3HT) and carbon nanotubes (CNT) composite thin films. The memory devices with FTO/P3HT-CNT/Al structure were fabricated by varying the CNT content in the composite. The memory device with 4% CNT in P3HT exhibited a typical bipolar resistive switching with set voltage of ∼1.8 V and a high ON/OFF ratio of >102. The nonvolatile behavior of the device has been studied by the retention test and showed good retention properties for >103 s. The resistance-temperature dependence of different resistance states has also been investigated. Ohmic conduction was found to be a dominant conduction mechanism in low bias region, whereas for the high voltage regime space charge limited conduction was found to be the ruling current conduction mechanism. Bipolar resistive switching characteristic of the nanocomposite film is explained on the basis of rupture and formation of carbon-rich filaments.