[9a-N205-1~10] 13.8 Optical properties and light-emitting devices

9:30 AM - 9:45 AM JST(12:30 AM - 12:45 AM UTC)English Presentation

[9a-N205-3] A new tri-layer Ni/Al/Au p-electrode in 281 nm UVB LED Boosted EQE to 4.6%

〇Hamida Zia^2,1, Amina Yasin², Kohei Fujimoto^1,2, Hiroyuki Yaguchi¹, M. Ajmal Khan², Hideki Hirayama² (1.Saitama University, 2.Riken)

Keywords:

UVB LED

We developed 281 nm UVB LEDs with improved LEE by incorporating a new combination of tri-layer Ni/Al/Au p-electrode with optimized thickness. Reciprocal space mapping confirmed partial relaxation in the n-Al_0.61Ga_0.39N buffer layer (~54%) relative to a fully relaxed AlN substrate, indicating good crystalline quality. Consequently, we optimized a Ni (10 nm)/Al(50 nm)/Au(100 nm) p-contact and conducted a comparative study on the same wafer under continuous-wave operation at room temperature using both the conventional Ni (20nm)/Au(100nm) p-contact and new tri-layer Ni(10nm)/Al(50nm)/Au (100nm) p-contact. An improve in the external quantum efficiency (EQE) of up to 4.6% compared to that of 4.2% EQE obtained from Ni (20nm)/Au (100nm) contact layer LED. Also, the light output power of 12 mW could be achieved. The Ni/Al/Au configuration demonstrated 35% higher reflectance and improved electrical conductivity, as observed in the I-V characteristics (Figure ). This enhancement is attributed to the combined effect of highly reflective Ni (10 nm), Al (50 nm), and Au (100 nm) layers, which significantly improve both optical and electrical properties. The current-voltage (I-V) characteristics of Ni/Al/Au LED is improved (Vf ~ 33 V at 20 mA), which is comparable to Ni/Au LED.