基於氮化鎵/氮化銦鎵奈米結構之發光元件

在本研究中我們有系統的探討氮化銦鎵�氮化鎵發光二極體的元件設計及其光學特性。首先我們以雙波長量子井結構，製做出藍綠光雙波長發光二極體，並由其所發藍光特性激發鎘化硒/硫化鋅之奈米晶體產生紅色光，而混合出發白光的發光元件。　　為進一步瞭解並改善雙波長發光二極體因電洞移動率較低，而使下層量子井發光效率減弱的因素，我們進設計了微米結構的發光二極體。在其表面均勻覆蓋電極，而使得在注入電流時主動層結合介面溫度提高，電洞移動率亦被提高，進而增加電子電洞結合放光的效率。同時，也使得在下層主動層的發光強度被提昇。　　另外，我們在成長氮銦化鎵�氮化鎵多重量子井前，預先長一層低濃度的氮化銦鎵量子井，來逹到預施應力之效果，以讓上層的量子井內銦成份增加，而使得波長可紅移約一百奈米，我們以此晶片成功製作橘紅光的發光二極體。　　此外為能充份瞭解氮銦化鎵�氮化鎵多重量子井其應力釋放的特性，我們用電子束顯影技術及乾式蝕刻方式，製做直徑約十奈米的氮銦化鎵�氮化鎵多重量子井奈米柱。在不同直徑的奈米柱頻譜改變關係中，顯示出除了量子侷限的影響之外，應力的釋放對氮銦化鎵�氮化鎵多重量子井之光學性有很大的影響。

關鍵字

白光發光二極體；硒化鎘/硫化鋅；氮化鎵/氮化銦鎵；量子侷限效應；奈米柱

並列摘要

In this research, we systematically investigate of InGaN/GaN quantum-well (QW) light-emitting diodes (LEDs) design and optics characteristics. First, we have grown and process a blue/green two-wavelength LED based on the mixture of two kinds of QW in epitaxial growth. We then coat CdSe/ZnS nano-crystals on the top of the two-wavelength LED for converting blue photons into red light. By coating such nano-crystals, the device emitted blue, green, and red lights for white-light generation. Also, we have fabricated blue/green two-wavelength, InGaN/GaN QW, flip-chip micro-LEDs of different mesa sizes by stacking different QWs. It is found that the blue-over-green contrast ratio of such an LED increased with the mesa size. The relatively stronger blue intensity in a device of larger mesa area is due to its higher operation junction temperature. For the emissions of yellow, orange, and red colors in InGaN/GaN QW LEDs, higher indium contents must be incorporated. Because of the 11 % lattice mismatch between GaN and InN, the miscibility between the two binary compounds becomes difficult when the indium content is higher than 15 % or so. We have demonstrated the operations of an orange and a red LED, which are fabricated with a pre-strained InGaN/GaN QW epi-structure. The pre-strain condition is created by growing a low-indium QW before the growth of five high-indium QWs. Finally, nanoposts with diameter down to around 10 nm are fabricated using electron-beam lithography and ICP RIE on an InGaN/GaN QW structure. Significant blue shifts in the PL spectra are observed. The blue shift range increases with decreasing post diameter. For the nanoposts with significant strain relaxation, the PL spectral peak positions became less sensitive to carrier screening. From the temperature-dependent PL and TRPL measurements and a numerical calculation of the effect of quantum confinement, we conclude that the optical behaviors of the nanoposts are mainly controlled by the combined effect of 3D quantum confinement and strain relaxation.

並列關鍵字

White light LED ； CdSe/ZnS ； GaN/InGaN ； quantum-confined Stark effect ； nano-post

參考文獻

1-1. I. Ozden, E. Makarona, A. V. Nurmikko, T. Takeuchi, and M. Krames, “A dual-wavelength indium gallium nitride quantum well light emitting diode,” Appl. Phys. Lett. Vol. 79, No, 16, pp. 2532-2534, Oct. 2001.

1-2. M. Yamada, Y. Narukawa, and T. Mukai, “Phosphor free high-luminous-efficiency white light-emitting diodes composed of InGaN multi-quantum well,” Jpn. J. Appl. Phys. Vol. 41, No. 3A, pp. L246-L248, Mar. 2002.

1-3. Y. D. Qi, H. Liang, W. Tang, Z. D. Lu, and K. M. Lau, “Dual wavelength InGaN/GaN multi-quantum well LEDs grown by metalorganic vapor phase epitaxy,” J. Crystal Growth Vol. 272, No. 1-4, pp. 333-340, 2004.

1-4. B. Damilano, N. Grandjean, C. Pernot, and J. Massier, ”Monolithic white light emitting diodes based on InGaN/GaN multiple-quantum wells,” Jpn. J. Appl. Phys. Part 2, Vol. 40, No. 9A/B, pp. L918-L920, Sept. 2001.

1-5. T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 84, 466 (2004).

國際替代計量

基於氮化鎵/氮化銦鎵奈米結構之發光元件

全文下載

主題瀏覽