Open AccessTransfer printing of vertical-type microscale light-emitting diode array onto flexible substrate using biomimetic stamp
Author(s) -
J. B. Park,
Won-Sik Choi,
Tae Hun Chung,
S. H. Lee,
Moon Kyu Kwak,
Jeongdae Ha,
Tak Jeong
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.006832
Subject(s) - microscale chemistry , polydimethylsiloxane , materials science , transfer printing , wafer , optoelectronics , adhesion , substrate (aquarium) , layer (electronics) , microcontact printing , bending , optics , flexible display , nanotechnology , composite material , oceanography , mathematics education , mathematics , physics , geology , thin film transistor
We report the transfer printing of GaN-based microscale vertical-type light-emitting diodes (μ-VLEDs) using a functional layer and a biomimetic stamp. An oxide-based functional layer is inserted onto the structure of a μ-VLED and used to separate the chip from the μ-VLED wafer by absorbing the pulse of a UV pulse laser during pick-up of the transfer printing process. Polydimethylsiloxane (PDMS)-based biomimetic stamps have been fabricated to mimic the gecko lizard cilia for improved adhesion and repeatability. The biomimetic stamp has an adhesion force of 25.6 N/cm 2 , which is 12 times the adhesion of a flat stamp; an adhesion force of 10 N/cm 2 or more was maintained after 100,000 repeated adhesion tests. A flexible 10 × 10 prototype array on a polyimide substrate was fabricated, and its bending test results indicated that the strain effect on the forward voltage and the output power was less than 1%. The stable bending test results of the prototype indicate that μ-VLEDs using biomimetic stamps allow the necessary stability for practical transfer printing.