|학술대회||2020년 가을 (11/18 ~ 11/20, 휘닉스 제주 섭지코지)|
|발표분야||F. 광기능/디스플레이 재료 분과|
|제목||Structural and Optical Investigation of Top-down Fabricated InGaN/GaN Nanowire Light-emitting Diodes.|
|초록||InGaN/GaN-based light emitting diodes (LEDs) has been spotlighted in the field of general illumination by superior advantages of III-V compounds, such as high efficiecy for luminescence, long lifetime, and robustness to humidity and operational stability. In recent, cylindrical shaped structured micro-scaled LEDs with high aspect ratio (called nanowire), rather than the conventional planar LEDs, are explored as an information self-emitting display device to replace the organic and quantum dot LEDs. Precedent researches have claimed lots of advantages of InGaN-based nanowire LEDs (NLEDs) against planar structured LEDs. For example, light extraction improvement, efficient light out-coupling, and weak blueshift of emission wavelength due to suppressed quauntum confiend Stark effects (QCSEs) are revealed. Meanwhile, coaxial multiple quantum structured NLEDs (called core-shell structure) have been studied to maximize the performace of nanowire LEDs in which himproved output light power due to larger emssion area to volume ratio and weak blueshift due to reduce of piezoelectric field in quantum wells (QW) appeared evident fromthe work by Lee et al.
In this work, the planar epitaxial structure for the fabrication of NLEDs was grown using metal organic chemical vapor deposition (MOCVD) on c-plane patterned sapphire substrate (PSS). The top-down fabrication approach was employed to produce the massive number of InGaN NLEDs. In other words, Cr layer, SiO2 layer, and self-assembled microspheres were sequentially deposited on the wafer and then used as the mulitple hard mask during the dry etching and pattern transfer. Following the release process of NLEDs from the substrate by the sonication in the solvent, free-stadning InGaN NLEDs with diameter of ~500 nm and length of 2.5 μm were obtained, also confirmed by by the scanning electron microscope (SEM). The optical and structural properties of NLEDs were analyzed by confocal photoluminescence (PL) and Raman system. The dynamic recombination process in InGaN NLEDs was also examined by the time-resolved photoluminescence. The details will be presented at the conference.
|키워드||<P>micro LEDs; GaN-based LEDs; light-emitting diodes</P>|