Effects of morphology and charge transport of PDIF-CN2 /graphene TFT

Abstract

A two dimensional form of carbon, Graphene has captured great interest in many fields due to its attractive physical and electrical properties. Recently, graphene based transistors are produced widely, which becomes in place of silicon in the coming years. Here, we studied the effect of integration n-type molecule with graphene to develop thin film transistors. Morphology and transfer characteristics of N,N′-1H,1H-perfluorobutyldicyanoperylene-carboxydi-imide(PDIF-CN2) islands on graphene are studied and compared the transfer characteristics of graphene TFT and PDIF-CN2/graphene TFT. CVD graphene is used to examine the growth and charge transport of PDIF-CN2/graphene TFT. 6.3 times increase in mobility has noticed after depositing PDIF-CN2 islands on graphene. ION/OFF ratio of PDIF-CN2/graphene TFT is 2 and Threshold voltage is 6.5 ± 1 V. The low ION/OFF ratio is due to the high quantity of PDIF-CN2 molecules. Observed linear behavior of ID at VDS =1 V, shows the absence of interface energy barrier for charge carrier injection, where gold electrodes were deposited on PDIF-CN2/ Graphene. Gold-PDIF-CN2 layer behave as ohmic contact, where the current-voltage (I-V) curve is linear as with Ohm's law. Morphological studies were conducted using Atomic Force Microscopy and Transmission Electron Microscopy. AFM studies reveal that size of PDIF-CN2 islands on graphene. The height of these islands is 35 nm and width is 350 nm. Different crystalline orientation has noticed by Transmission Electron Microscopy.