Double-side step-graded AlGaN electron blocking layer for nearly droop-free GaN-based blue LEDs

Abstract

Double-side step-graded AlGaN electron blocking layer (EBL) for InGaN/GaN based LEDs with emission wavelength at 415 nm is proposed to develop nearly droop-free performance. The performance comparison of LEDs with double-side step-graded EBL and with conventional EBL reveals that the proposed structure yields 31.50% improved IQE, three-fold higher output power with a very low efficiency droop ∼ (5%) at the current density of 200 A/cm 2 . Such noticeable improvement is justified by critically analyzing and comparing both of the structures in terms of band structure, carrier concentration, electrostatic field and radiative recombination rate. Analysis confirms that double-side step-graded EBL results in superior electron confinement, increased hole injection and higher radiative recombination rate for LEDs. • For the first time Blue-LED with extraordinary droop control has been explored and reported. • Slight variation in the parameters like radiative recombination and electrostatic field have been critically analysed. • Analysis and confirmation of double-side step-graded EBL which results in superior electron confinement. • Effect of double-side step-graded EBL in increasing injection and radiative recombination rate has been reported.