High-temperature electroluminescence properties of InGaN red 40 × 40 μ m2 micro-light-emitting diodes with a peak external quantum efficiency of 3.2%

Abstract

We study the high-temperature electroluminescence properties of 600 nm InGaN red 40 × 40 μm2 micro-light-emitting diodes (μLEDs) with a peak external quantum efficiency (EQE) of 3.2%. Temperature-dependent peak wavelength measurements show a low redshift of 0.05 nm/K. The injection efficiency improves with increasing temperature. The hot/cold (HC) factor is used to quantify the thermal droop: at 400 K, the EQE and wall-plug efficiency HC factors at 50 A/cm2 reach high values of 0.72 and 0.85, respectively. This demonstrates the robustness of InGaN red μLEDs up to high temperature, with a much-improved stability over conventional AlInGaP red μLEDs.

Progress of InGaN-Based Red Micro-Light Emitting Diodes

“…In 2021, Li et al from UCSB demonstrated significant progress of InGaN red µLEDs on PSS [5][6][7]. As discussed in Section 2.1, the packaged 607 nm InGaN red µLEDs show a peak EQE of 2.4% to 2.6% as the size reduces from 100 × 100 µm 2 to 20 × 20 µm 2 .…”

“…In contrast, InGaN red µLEDs show a robust thermal property. P. Li et al from UCSB investigated the high-temperature EL properties from 300 K to 400 K of InGaN red µLEDs (40 × 40 µm 2 ) [7,14]. The 600 nm InGaN red µLEDs show a high peak EQE of 3.2%.…”

“…Micro-size light-emitting diodes (µLEDs) have attracted huge attention as the nextgeneration display technology for wide applications, such as wearable watches, virtual/augmented reality, micro-projectors, and ultra-large televisions [1][2][3][4]. InGaN-based red µLEDs have become the research focus now [5][6][7][8]. To achieve red emission, the indium composition in the InGaN quantum wells (QWs) should be greater than 35%, which causes a lot of challenges.…”

“…Our group has reported high efficiency InGaN green LEDs using AlGaN cap layer grown on top of InGaN green QWs [15]. More recently, we reported InGaN red µLEDs with an EQE over 3% using similar active region design [5][6][7]. Other novel growth strategies have been proposed to achieve InGaN red µLEDs, such as InGaNOS pseudo-substrate [16][17][18][19], nano-porous GaN [20], strain relaxed InGaN buffer layer using in-situ InGaN decomposition layer [21,22].…”

Interfacial modulation and plasmonic effect mediated high-brightness green light sources in a single Ga-doped ZnO microwire based heterojunction

“…Currently, InGaN/GaN multi-quantum-well materials and structures have been intensively studied and identified as an emerging platform for constructing wavelength-tunable LEDs due to their continuously variable bandgap ranging from 0.7 to 3.4 eV. [1][2][3][4][5][6] Particularly, display technology based on micro-and nano-sized LEDs has attracted significant attention for comprehensive applications, including ultrahigh resolution lighting and displays, biomedical imaging, augmented/virtual reality, sensing, etc. For nearly two decades, painstaking efforts have been carried out to shrink the areal sizes of traditional InGaNbased materials, structures and devices.…”