title: Vertically stacked color tunable light-emitting diodes fabricated using wafer bonding and transfer printing.
abstract: We report on the vertically stacked color tunable light-emitting diodes (LEDs) fabricated using wafer bonding with an indium tin oxide (ITO) layer and transfer printing by the laser lift-off process. Employing optically transparent and electrically conductive ITO as an adhesion layer enables to bond the GaN-based blue and AlGaInP-based yellow LEDs. We find out that the interdiffusion of In, O, and Ga at the interface between ITO and GaP allows the strong bonding of the heterogeneous optoelectronic materials and the integration of two different color LEDs on a single substrate. The efficacy of this method is demonstrated by showing the successful control of color coordinate from the vertically stacked LEDs by modulating the individual intensity of blue and yellow emissions.
authors.affiliation: Department of Nanobio Materials and Electronics and ‡School of Materials Science and Engineering, Gwangju Institute of Science and Technology , Gwangju 500-712, Republic of Korea.
authors.forename: Jaeyi
authors.initials: J
authors.lastname: Chun
authors.forename: Kwang Jae
authors.initials: KJ
authors.lastname: Lee
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Leem
authors.forename: Won-Mo
authors.initials: WM
authors.lastname: Kang
authors.forename: Tak
authors.initials: T
authors.lastname: Jeong
authors.forename: Jong Hyeob
authors.initials: JH
authors.lastname: Baek
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Lee
authors.forename: Bong-Joong
authors.initials: BJ
authors.lastname: Kim
authors.forename: Seong-Ju
authors.initials: SJ
authors.lastname: Park
keywords: ITO adhesion layer; color tunable light-emitting diodes; transfer printing; vertical integration; wafer bonding