Photoelectrochemical liftoff of LEDs grown on freestanding c-plane GaN substrates.
We demonstrate a thin-film flip-chip (TFFC) process for LEDs grown on freestanding c-plane GaN substrates. LEDs are transferred from a bulk GaN substrate to a sapphire submount via a photoelectrochemical (PEC) undercut etch. This PEC liftoff method allows for substrate reuse and exposes the N-face of the LEDs for additional roughening. The LEDs emitted at a wavelength of 432 nm with a turn on voltage of ~3 V. Etching the LEDs in heated KOH after transferring them to a sapphire submount increased the peak external quantum efficiency (EQE) by 42.5% from 9.9% (unintentionally roughened) to 14.1% (intentionally roughened).
David
D
Hwang
Benjamin P
BP
Yonkee
Burhan Saif
BS
Addin
Robert M
RM
Farrell
Shuji
S
Nakamura
James S
JS
Speck
Steven
S
DenBaars