Defect reduction in (11–22) semipolar GaN with embedded InN islands on m-plane sapphire

Abstract

This paper reports on the improved properties of semipolar (11–22) GaN with embedded InN islands on m-plane sapphire substrate. The crystal quality of GaN grown over embedded InN islands was improved by the defect blocking mechanism that the InN islands stop from propagating of dislocations. The full width at half maximum (FWHM) of X-ray rocking curves for the on- and off-axes planes of GaN with embedded InN islands significantly narrowed. The photoluminescence (PL) intensity of GaN with embedded InN islands increased by 28% compared with that of GaN without InN islands (reference GaN). The n-type GaN carrier mobility was analyzed by using temperature-dependent Hall effect measurement. The increase in peak mobility at 350K from 104 to 113cm2/Vs with embedded islands also suggested the effectiveness of embedded InN islands in GaN. LEDs fabricated on (11–22) GaN with embedded InN islands showed approximately 2.7 times higher optical output power than the reference LED at 100mA.