Wafer-Scale Heterogeneous Integration of High-Resolution Micro-LED Displays with Carbon Nanotube Thin-Film Transistors.

Abstract

Direct-view micro-light-emitting-diode (micro-LED) displays demand thin-film transistors (TFTs) that offer high driving current together with low-temperature and scalable fabrication. Semiconducting carbon nanotube TFTs (CNT-TFTs) are promising candidates due to their driving capability and simple process. However, the large-area heterogeneous integration of carbon and compound semiconductor devices with panel-compatible processes remains a major challenge. Here, we address this by demonstrating a direct-view micro-LED display driven by glass-substrate CNT-TFT backplanes. The prototype features a 1.68 in. panel with 117 600 micro-LEDs, achieving a pixel density of 300 PPI, setting a benchmark in both size and resolution for micro-LED displays using low-dimensional semiconductor TFTs. To realize this, a CNT backplane technology processed within 250 °C on 4 in. glass was developed, incorporating an etch-stop layer (ESL) technique to ensure uniformity and manufacturing compatibility. Through a nitrogen annealing process that passivates both interface and bulk charge traps, combined with a yttrium oxide (Y₂O₃) interlayer, the driving and switching capability was significantly enhanced, achieving a field-effect mobility of 30.1 cm² V^-1 s^-1 and on/off ratio of 1.09 × 10⁷ at 16 μm channel length. This work establishes a scalable approach for large-area, high-pixel-density direct-view micro-LED panels enabled by carbon electronics for next-generation display applications.