Wafer-Scale Fabrication of Separated Carbon Nanotube Thin-Film Transistors for Display Applications

Abstract

Preseparated, semiconductive enriched carbon nanotubes hold great potential for thin-film transistors and display applications due to their high mobility, high percentage of semiconductive nanotubes, and room-temperature processing compatibility. Here in this paper, we report our progress on wafer-scale processing of separated nanotube thin-film transistors (SN-TFTs) for display applications, including key technology components such as wafer-scale assembly of high-density, uniform separated nanotube networks, high-yield fabrication of devices with superior performance, and demonstration of organic light-emitting diode (OLED) switching controlled by a SN-TFT. On the basis of separated nanotubes with 95% semiconductive nanotubes, we have achieved solution-based assembly of separated nanotube thin films on complete 3 in. Si/SiO(2) wafers, and further carried out wafer-scale fabrication to produce transistors with high yield (>98%), small sheet resistance ( approximately 25 kOmega/sq), high current density ( approximately 10 microA/microm), and superior mobility ( approximately 52 cm(2) V(-1) s(-1)). Moreover, on/off ratios of >10(4) are achieved in devices with channel length L > 20 microm. In addition, OLED control circuit has been demonstrated with the SN-TFT, and the modulation in the output light intensity exceeds 10(4). Our approach can be easily scaled to large areas and could serve as critical foundation for future nanotube-based display electronics.

Fundamental Performance Limits of Carbon Nanotube Thin-Film Transistors Achieved Using Hybrid Molecular Dielectrics

“…19,39 Note also that reduced on/off ratios result from high densities of monodisperse CNTs due to increased CNT-CNT screening. 6,18 The present CNT films afford the highest normalized on-state conductance at an on/off ratio = 10 6 reported to date for CNT TFTs.…”

Chirality-controlled synthesis of single-wall carbon nanotubes using vapour-phase epitaxy

“…Selective synthesis of semiconducting or metallic predominated SWCNTs has already been achieved through controlled chemical vapour deposition (CVD) growth [16][17][18] , enabling the fabrication of nanotube field-effect transistors using predominantly semiconducting SWCNTs 19,20 . As a next step, synthesis of SWCNTs with predefined chirality is highly desired.…”

Capacitance-Voltage Characteristics of Thin-film Transistors Fabricated with Solution-Processed Semiconducting Carbon Nanotube Networks

“…On the other hand, using random networks of carbon nanotubes for applications in thin-film transistors (TFTs) has recently shown great promise. Such devices offer mechanical flexibility and optical transparency and can be easily fabricated in a scalable fashion with far superior device performance and long-term air-stability compared with amorphous silicon or organic semiconductors [5][6][7][8][9][10][11]. Among various approaches used for assembling random carbon nanotube networks, solution-processed semiconductor-enriched carbon nanotubes possess additional advantages of low-cost and room temperature processes [6,[8][9][10]12].…”

“…Such devices offer mechanical flexibility and optical transparency and can be easily fabricated in a scalable fashion with far superior device performance and long-term air-stability compared with amorphous silicon or organic semiconductors [5][6][7][8][9][10][11]. Among various approaches used for assembling random carbon nanotube networks, solution-processed semiconductor-enriched carbon nanotubes possess additional advantages of low-cost and room temperature processes [6,[8][9][10]12]. With the ongoing pavement towards reliable dispersion of longer nanotubes with higher purity separation process [13], largescale, high-performance, flexible carbon nanotube TFTs have already found wide applications in compliant integrated circuits, organic light-emitting displays, and electronic skins [5,9,11,14].…”