Work

Size-dependent effects of TMAH sidewall treatment for enhanced modulation bandwidth of GaN-based micro-LEDs

Year: 2026

Type: article

Abstract: This work investigates the size-dependent effects of tetramethylammonium hydroxide (TMAH) sidewall treatment on the static optoelectronic properties and high-speed modulation characteristics of GaN-based micro-LEDs. Devices with side lengths of 10, 20, and 30 μm were treated for 0, 30, 60, and 120 min. Appropriate TMAH treatment effectively modified the dry-etching-induced sidewall morphology, improved luminous efficiency, and reduced sidewall-related parasitic capacitance, thereby alleviating RC-related limitations. The influence of TMAH treatment duration on the modulation performance exhibited a pronounced size dependence. After 60 min of treatment, the 10 μm devices achieved the highest average -3 dB bandwidth of approximately 1.57 GHz, representing a 45% improvement compared with the untreated devices. In contrast, as the device size increased to 20 and 30 μm, the bandwidth differences among different TMAH treatment durations became progressively smaller, and the overall dependence on treatment duration was less pronounced. These results demonstrate a size-dependent response to TMAH treatment under the investigated process conditions, arising from the interplay among sidewall modification, mesa-geometry preservation, carrier dynamics, and electrical parasitics, thereby providing a practical strategy for high-speed visible light communication.

Source: Optics Express

DOI: 10.1364/oe.613193