title: Highly reliable Ag/Zn/Ag ohmic reflector for high-power GaN-based vertical light-emitting diode.
abstract: We report the improved performance of InGaN/GaN-based light-emitting diodes (LEDs) through Ag reflectors combined with a Zn middle layer. It is shown that the Zn middle layer (5 nm thick) suppresses the agglomeration of Ag reflectors by forming ZnO and dissolving into Ag. The Ag/Zn/Ag contacts show a specific contact resistance of 6.2 × 10(-5) Ωcm(2) and reflectance of ~83% at a wavelength of 440 nm when annealed at 500 °C, which are much better than those of Ag only contacts. Blue LEDs fabricated with the 500 °C-annealed Ag/Zn/Ag reflectors show a forward voltage of 2.98 V at an injection current of 20 mA, which is lower than that (3.02 V) of LEDs with the annealed Ag only contacts. LEDs with the 500 °C-annealed Ag/Zn/Ag contacts exhibit 34% higher output power (at 20 mA) than LEDs with the annealed Ag only contacts.
authors.affiliation: Department of Materials Science and Engineering, Korea University, Seoul, South Korea.
authors.forename: Woong-Sun
authors.initials: WS
authors.lastname: Yum
authors.forename: Joon-Woo
authors.initials: JW
authors.lastname: Jeon
authors.forename: Jun-Suk
authors.initials: JS
authors.lastname: Sung
authors.forename: Tae-Yeon
authors.initials: TY
authors.lastname: Seong
mesh_terms: D017097:Electric Impedance; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry*; D007909:Lenses; D008029:Lighting / Q000295:instrumentation*; D010363:Pattern Recognition, Automated / Q000379:methods*; D012666:Semiconductors; D012834:Silver / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: C473348:gallium nitride; D012834:Silver; D005708:Gallium; D015032:Zinc