Study of laser-debonded GaN light emitting diodes

Abstract

We report experimental investigation of laser-assisted debonding of GaN-based light emitting diodes (LEDs) grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. The sapphire substrate was debonded from the GaN material using an excimer laser. The unintentionally doped GaN surface was photo-electrochemically (PEC) etched to form hexagonal pyramid hillocks on the surface, using HeCd laser as the light source. The luminous intensities of the debonded and roughened LEDs at different etching time, as a function of different surface roughness, have been reported. In this experiment, the greatest improvement in the luminous intensities has been achieved at 40mins etching and increased by 60% when compared to the LEDs on sapphire. This increase is attributed to the enhancement in photon extraction efficiency. © 2006 Materials Research Society.