The scaling of the microLED and the advantage of 2D materials

TL;DR

This paper explores how reducing LED thickness and using 2D materials like fluorinated graphene can improve microLED performance and scalability for next-generation high-resolution displays.

Contribution

It introduces the synthesis of partially fluorinated graphene for red and green emission and demonstrates lithographic color patterning for microLED scaling.

Findings

Reducing LED thickness decreases sidewall leakage and internal reflection.

Partially fluorinated graphene emits red and green light suitable for microLEDs.

Lithographic patterning enables multi-color microLEDs for high-resolution displays.

Abstract

The demand for higher resolution displays drives the demand for smaller pixels. Displays show a trend of doubling the pixel number every 4 years and doubling the pixel per inch (PPI) every 6 years. As the prospective candidate for next-generation display technology, microLED (micro Light Emitting Diode) will suffer from sidewall current leakage and poor extraction efficiency as its lateral size reduces. Using Finite Element Analysis (FEA) method and Finite-Difference Time-Domain (FDTD) method, we find that reducing the thickness of the LED can reduce the current leaking to the sidewalls and reduce the total internal reflection simultaneously. A promising solution to this problem is by using atomically thin 2D materials to make LEDs. However, monolayer inorganic 2D materials that can provide red, green and blue emission are still lacking. Based on the blue light-emitting material fluorographene (CF), partially fluorinated graphene (CFx) is synthesized in this work to emit red and green colors from 683 nm to 555 nm (limited by the instrument). This work also demonstrates lithographically defined regions with different colors, paving the way for the scaling of microLED.