Efficient yellow and green emitting InGaN/GaN nanostructured QW materials and LEDs

2016-12-06Efficient green emitting LEDs and monolithic white light emitting LEDs require the extension of the range of efficient light emission in the GaN/InGaN materials system. We demonstrate high efficiency green and yellow light emitting multiple quantum well (MQW) structures grown on GaN nanostripe templates. The structures show promise for realizing high‐efficiency phosphor‐free white LEDs. The nanostripe dimensions range from 100 nm to 300 nm and have separations that range from 300 nm to 1 micron. Such small lateral dimensions are chosen to promote the elimination of threading dislocations from the structures. Nanostripes with various semipolar surfaces are grown with selective area growth on e‐beam lithography patterned c‐plane GaN where the mask openings are oriented between the [10‐10] and [11‐20] directions. Photoluminescence (PL) measurement shows that MQWs grown on stripes with (10‐11) surfaces and triangular shape emit the longest peak wavelength and have the best surface stability. Efficient PL emission peak wavelengths as long as 570 nm are realized on the triangular stripes with (10‐11) surfaces by optimizing the MQW growth conditions for long wavelength emission. Power dependent PL measurement shows linear response over more than three orders of magnitude of excitation power, indicating high radiative recombination efficiency. LED structures that utilize MQWs grown on nanostripes with (10‐11) surfaces were fabricated to further demonstrate the viability of the approach