Lift-off of semipolar blue and green III-nitride LEDs grown on free-standing GaN

Abstract

Light emitting diodes (LEDs), with active blue and green emitting and sacrificial multi-quantum well layers, were epitaxially grown using metal organic chemical vapor deposition on free-standing semipolar (20 2 ¯ 1) GaN substrates. NanoLEDs were then fabricated and released into solution using an approach based on forming a mm-scale mesa, Au-Au thermocompression bonding to a submount, large-area photoelectrochemical etching, and colloidal lithography. Photo- and cathodoluminescence (CL) measurements demonstrated that nanoLEDs were optically active after fabrication and released into the solution. Monte Carlo simulations of the electron trajectory through GaN/InGaN were performed to understand the patterns shown in CL images. The fabrication process developed herein could provide a viable route to highly efficient, nanoscale blue and green light emitters for applications in next-generation display technologies.