| 학회 | 한국재료학회 |
| 학술대회 | 2011년 봄 (05/26 ~ 05/27, 제주 휘닉스 아일랜드) |
| 권호 | 17권 1호 |
| 발표분야 | F. Display and optic Materials and processing(디스플레이 및 광 재료) |
| 제목 | Fabrication and Optical Characterization of AlGaN/InGaN Multiple Quantum Well Nanopillar Ultar Violet Light Emitting Diodes |
| 초록 | Nitride-based semiconductors have been recognized as major direct band gap materials for many applications in the area of optoelectronic devices and high-temperature/ power electronic devices in the region of visible light. UV LEDs with emission wavelengths below 360 nm require the use of ternary AlGaN or quaternary AlInGaN active layers. In the past, several groups have demonstrated UV LEDs with peak emission wavelength around 360 nm using AlGaN/InGaN MQWs in the active region. For AlGaN/InGaN multiple quantum well (MQW)-based LED, the nanopillar structures may relieve strain and thus accommodate the large lattice mismatch at hetero-interface, which can enhance the radiative recombination efficiency and thus the internal quantum efficiency of the LED device. Due to the large sidewall surface of nanopillars, light extract efficiency can also be improved. In addition, the inclined threading dislocations may cease in the nanopillar’s side surface and decrease dislocation density, which can reduce the nonradiative recombination efficiency and thus improves the device performance significantly. AlGaN/InGaN-multiple-quantum-well-based light emitting diode (LED) nanopillar arrays with a diameter of approximately 100~200 nm and a height of 1.0 um are fabricated by inductively coupled plasma etching using Ni self-assembled nanodots as etching mask. In comparison to the as-grown LED sample an enhancement by a factor of four of photoluminescence (PL) intensity is achieved after the fabrication of nanopillars, and a blue shift and a decrease of full width at half maximum of the PL peak are observed. The method of additional annealing and wet etching with different chemical solutions is used to remove the etch-induced damage. The result shows that the dilute HCl (HCl:H2O=1:1) and BOE treatment is the most effective. The PL intensity of nanopillar UVLEDs after such a treatment is about 8.0 times stronger than that before treatment. |
| 저자 | 윤재식1, 김재관2, 이지면2 |
| 소속 | 1한국기초과학지원(연), 2순천대 |
| 키워드 | UVLED; AlGaN/InGaN MQWs; Nano pillar |
