Dilute and Percolating Carbon Nanotube (CNT) Thin Film Metrology, Optimization, and Characterization for Use in Next-Generation Display Applications

The Carbon Nanotube Enabled Vertical Organic Light Emitting Transistor (CN-VOLET) shows great promise to drastically improve the specifications of current OLED display technologies and circumvent challenges in their production relating to cost and processing difficulties. An ultra-thin film consisting of a CNT network must posses a number of characteristics to enable its use as a source electrode in a stable and optimized VOLET device. The CNT network must be dense enough to be percolating yet dilute (non-continuous, web-like) enough to allow the gate field in this vertical architecture to permeate through it and modulate the Schottky barrier at the source-channel interface. Here we present the theoretical and experimental work done to measure and optimize the quality of these films and their derivative devices through experimental, theoretical, and computational techniques. Namely, we present a way to theoretically predict the level of diluteness and percolation for different CNT mass densities and a computer algorithm which visually identifies deposited tubes in atomic force microscopy (AFM) images to calculate the surface coverage. We then present some results of the fabricated devices and their performance.