title: High performance of GaN-based flip-chip light-emitting diodes with hole-shape patterned ITO ohmic contact layer and AgIn reflector.
abstract: The enhancement of light extraction efficiency is observed when the hole-shape patterned ITO ohmic contact layer and AgIn reflector is adopted in GaN-based flip-chip (FC) light emitting diodes (LEDs). ITO layer (140 nm) and AgIn (200 nm) was deposited on the top of p-GaN by in-line DC sputtering and electron beam evaporating system, respectively. The ITO ohmic contact layer showed a low specific contact resistance of 2.66 x 10(-5) Omega cm(-2) and high transmittance of >85% at visible spectral regions. The AgIn reflector exhibited a low specific contact resistance of 1.90 x 10(-5) Omega cm(-2) and high reflectance of approximately 84% at visible spectral regions. Comparing with unpatterned ITO/AgIn layer, the optical output power of GaN-based FC LEDs improves approximately 30% by the adoption of micro size hole-shape patterned ITO ohmic contact layer and AgIn reflector.
authors.affiliation: Korea Photonics Technology Institute, Gwangju 500-460, Korea.
authors.forename: Sang Hern
authors.initials: SH
authors.lastname: Lee
authors.forename: Jong Hyeob
authors.initials: JH
authors.lastname: Baek
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Kim
authors.forename: Lee Soon
authors.initials: LS
authors.lastname: Park