Investigation of Electrical Properties and Reliability of GaN-Based Micro-LEDs

Ke Zhang; Yibo Liu; Hoi-Sing Kwok; Zhaojun Liu

doi:10.3390/nano10040689

Investigation of Electrical Properties and Reliability of GaN-Based Micro-LEDs

Nanomaterials (Basel). 2020 Apr 6;10(4):689. doi: 10.3390/nano10040689.

Authors

Ke Zhang^{1

2}, Yibo Liu¹, Hoi-Sing Kwok^{1

2}, Zhaojun Liu^{1

2}

Affiliations

¹ Department of Electrical and Electronic Engineering, The Southern University of Science and Technology, Shenzhen 518000, China.
² Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong SAR 999077, China.

Abstract

In this paper, we report high-performance Micro-LEDs on sapphire substrates, with pixel size scaling to 20 µm and an ultra-high current density of 9902 A/cm². The forward voltages (V_F) of the devices ranged from 2.32 V to 2.39 V under an injection current density of 10 A/cm². The size and structure-dependent effects were subsequently investigated to optimize the device design. The reliability of Micro-LED devices was evaluated under long-aging, high-temperature, and high-humidity conditions. It was found that Micro-LED devices can maintain comparable performance with an emission wavelength of about 445 nm and a full width at half maximum (FWHM) of 22 nm under extreme environments. Following this, specific analysis with four detailed factors of forward voltage, forward current, slope, and leakage current was carried out in order to show the influence of the different environments on different aspects of the devices.

Keywords: GaN-based micro-LEDs; micro-LED display; reliability test.