Efficient Semipolar (11–22) 550 nm Yellow/Green InGaN Light-Emitting Diodes on Low Defect Density (11–22) GaN/Sapphire Templates

Abstract

We demonstrate efficient semipolar (11-22) 550 nm yellow/green InGaN light-emitting diodes (LEDs) with InGaN barriers on low defect density (11-22) GaN/patterned sapphire templates. The InGaN barriers were clearly identified, and no InGaN clusters were observed by atom probe tomography measurements. The semipolar (11-22) 550 nm InGaN LEDs (0.1 mm size) show an output power of 2.4 mW at 100 mA and a peak external quantum efficiency of 1.3% with a low efficiency drop. In addition, the LEDs exhibit a small blue-shift of only 11 nm as injection current increases from 5 to 100 mA. These results suggest the potential to produce high efficiency semipolar InGaN LEDs with long emission wavelength on large-area sapphire substrates with economical feasibility.

Three-dimensional hierarchical semi-polar GaN/InGaN MQW coaxial nanowires on a patterned Si nanowire template

“…QCSE can be suppressed by growing the GaN/ InGaN MQWs on either a nonpolar growth facet or a semi-polar growth facet such as (11 22) and (20 21), and additionally, the semi-polar growth facet may accommodate more indium incorporation than the nonpolar and polar surfaces. 27,28 Therefore, the semi-polar growth of GaN/InGaN MQWs is the most preferred and is currently actively studied for GaN-based optical applications in leading laboratories. [29][30][31][32][33][34] In this work, we fabricate the next-generation 3-D semipolar GaN/InGaN hierarchical NWs grown on a Si NWtemplate and characterize their optical properties.…”

High Quality, Mass‐Producible Semipolar GaN and InGaN Light‐Emitting Diodes Grown on Sapphire

“…The peak EQE of semipolar/nonpolar LEDs grown on sapphire or SiC substrates has been summarized and shown in Figure d . The (201) green LED demonstrated in this work shows state‐of‐the‐art EQE for semipolar/nonpolar LEDs heteroepitaxially grown on sapphire or SiC substrates . The preliminary result of green LEDs built on the (201) GaN/sapphire templates provides clear evidence of the benefit of the elimination of SFs.…”

“…We have surveyed the literature about semipolar/nonpolar LEDs grown on sapphire or SiC substrates reported by other research groups. The peak EQE of semipolar/nonpolar LEDs grown on sapphire or SiC substrates has been summarized and shown in Figure d . The (201) green LED demonstrated in this work shows state‐of‐the‐art EQE for semipolar/nonpolar LEDs heteroepitaxially grown on sapphire or SiC substrates .…”

Effects of a Reduced Effective Active Region Volume on Wavelength-Dependent Efficiency Droop of InGaN-Based Light-Emitting Diodes

“…Such a significantly reduced effective active region volume is ascribed to inhomogeneous carrier distributions in localized centers, as well as less overlap of electron-hole wave-functions by large piezoelectric fields. The shrink in effective volume of InGaN QW can be evidenced by the experimental confocal micro-photoluminescence [18,20], near-field scanning optical microscopy [17,27], and atom probe tomography [28]. In addition, spatial fluctuations in indium composition have been theoretically modeled to investigate the carrier localization effect [18] and device performance [19].…”