Transferable, flexible white light-emitting diodes of GaN p-n junction microcrystals fabricated by remote epitaxy

Abstract

The remote epitaxy of GaN p-n homojunction microcrystals (mu Cs) is demonstrated for fabricating transferable, flexible white light-emitting diodes (WLEDs). The GaN p-n junction mu Cs are randomly grown on graphene-coated Al2O3(0001), which are then delaminated for mass-transfer onto conducting copper tape. The mu Cs-LED shows electrical rectification and white electroluminescence (EL) emission. The mu Cs-WLED exhibits reliable LED performances after repetitive bending deformations and cycling temperature environments. Based on the transferability, the mu Cs-WLEDs are patterned and assembled to matrix arrays, which exhibit homogeneous, reliable performances even at a bent form. We discuss that the origin of white EL emission is mixing of blue and yellow-red EL emissions from p-GaN and n-GaN sides, respectively, based on photoluminescence spectroscopic measurements. This study opens a way of fabricating the transferable, flexible, and modular light panels through remote epitaxy.