Development of Ultrahigh Efficiency Compound Semiconductor Quantum Wire Light-Emitting Diodes

超高效率化合物半导体量子线发光二极管的研制

• 批准号: 17360170
• 负责人: WANG Xuelun
• 金额: $ 7.78万
• 依托单位: National Institute of Advanced Industrial Science and Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360170/
• 关键词: Light-emitting diode; Light-extraction efficiency; Spontaneous emission; Patterned substrate; Quantum well; Internal quantum efficiency; Quantum wire; 指向性; V溝基板; 導波路

High-efficiency semiconductor light-emitting diodes(LEDs) have attracted great current interests as an energy-efficient and long-lifetime general lighting device of the 21st century. However, in conventional LEDs which are usually grown on flat substrates, it's very difficult to extract light generated in semiconductors to the outside free space with a high efficiency due to the existence of total internal reflection at the semiconductor-air interface, blocking of light by opaque metal electrodes, and light absorption by substrates. The objective of the present project is to realize semiconductor LEDs with light-extraction efficiencies much higher than those of conventional devices using spontaneous emission control technique based on selective growth on pre-patterned, nonplanar substrates. The main achievements are summarized as following.1. Proposal and demonstration of "LED with separated current-injection and light-emitting areas" : We proposed and demonstrated a new type of semico … More nductor LED with separated current-injection and light-emitting areas, aimed at greatly suppressing light blocking by opaque metal electrodes, utilizing the fact that bandgap energies of compound semiconductor layers grown on patterned substrates usually change with crystalline facets. The basic idea of this new device is to form the Ohmic electrodes selectively on the high-bandgap-energy facets of the epitaxial layers. In this device, carriers injected from the high-bandgap-energy facets will first diffuse, through barrier and/or quantum well(QWL) active layers, to the adjacent low-bandgap-energy facets and then recombine there. In this way, we can spatially separate the current-injection area from the light-emitting area and thus greatly suppress the blocking of light by metal electrodes.2. Discovery of a new high-efficiency spontaneous emission control phenomenon: We found that both the light-extraction efficiency and the internal quantum efficiency of the (001) flat QWL grown on the narrow ridge-top region (lateral width < 1μm) of a V-grooved GaAs substrate can be dramatically enhanced just by surrounding the (001) QWL with high Al-composition layers in both the growth and the lateral directions. For example, we have shown by photoluminescence study that more than 60% of the spontaneous emission from an Al_<0.3>Ga_<0.7>AS/GaAS/Al_<0.3>Ga_<0.7>As(001) QWL can be extracted to the outside space by surrounding the above QWL structure with Al_<0.65>Ga_<0.35>As barrier layers. Moreover, the internal quantum efficiency of the above Al_<0.3>Ga_<0.7>AS/GaAS/Al_<0.3>Ga_<0.7>As(001) QWL structure was found to be 100% even at room temperature, which is more than 10 times higher compared with that of sample without the Al_<0.65>Ga_<0.35>As barrier layers. High-efficiency LEDs are being developed currently using this unique spontaneous emission control technique. Less

高效率半导体发光二极管（LED）作为21世纪世纪的节能和长寿命的通用照明器件已经吸引了巨大的当前兴趣。然而，在通常生长在平坦衬底上的常规LED中，由于在半导体-空气界面处存在全内反射、不透明金属电极对光的阻挡以及衬底对光的吸收，因此很难将半导体中产生的光高效地提取到外部自由空间。本项目的目的是实现半导体LED的光提取效率远远高于传统的设备，使用自发辐射控制技术的基础上选择性生长的预图案化，非平面基板。主要研究成果如下：1.“电流注入区和发光区分离的LED”的提出和演示：我们提出并演示了一种新型的半导体器件， ...更多信息 具有分离的电流注入区和发光区的半导体LED，其目的在于利用在图案化衬底上生长的化合物半导体层的带隙能量通常随结晶面而变化的事实，极大地抑制由不透明金属电极引起的光阻挡。这种新器件的基本思想是在外延层的高带隙能面上选择性地形成欧姆电极。在该器件中，从高带隙能量刻面注入的载流子将首先通过势垒和/或量子阱（QWL）有源层扩散到相邻的低带隙能量刻面，然后在那里复合。通过这种方式，我们可以在空间上将电流注入区域与发光区域分开，从而大大抑制金属电极对光的阻挡。发现了一种新的高效自发辐射控制现象：我们发现，在V型槽GaAs衬底的窄脊顶区（横向宽度< 1μm）上生长的（001）平坦QWL，只要在生长方向和横向上用高Al组份层包围（001）QWL，就可以显著提高其光提取效率和内量子效率。例如，我们已经通过光致发光研究表明，超过60%的自发辐射从Al_<0.3>Ga_<0.7>AS/GaAS/Al_<0.3>Ga_<0.7>As（001）QWL可以提取到外部空间通过包围上述QWL结构与Al_<0.65>Ga_<0.35>As阻挡层。此外，在室温下，Al_<0.3>Ga_<0.7>AS/GaAS/Al_<0.3>Ga_<0.7>As（001）QWL结构的内量子效率为100%，比未加Al_ Ga_ As阻挡层的样品的内量子效率高10倍以上<0.65><0.35>。目前正在使用这种独特的自发发射控制技术开发高效率LED。少

项目成果

Observation of Very High Spontaneous Emission Extraction Efficiency from Semiconductor Nanostructures on Patterned Substrates

观察图案化基板上的半导体纳米结构的极高自发发射提取效率

• 发表时间: 2008
• 作者: 古江重紀;王 学論;X. -L. Wang and S. Furue.
• 通讯作者: X. -L. Wang and S. Furue.

Semiconductor Light-Emitting Diodes with Separated Current-Injection and Light-Emitting Areas

具有分离的电流注入区和发光区的半导体发光二极管

• 发表时间: 2006
• 作者: 古江重紀;王 学論;X. -L. Wang and S. Furue.;X. -L. Wang and S. Furue.;X. -L. Wang and S. Furue.;X.-L.Wang;X. -L. Wang.
• 通讯作者: X. -L. Wang.

半導体発光ダイオード

半导体发光二极管

• 发表时间: 2010

形状基板を用いた高効率発光ダイオードの提案・試作

使用成形基板的高效发光二极管的提案和原型设计

• 发表时间: 2008
• 作者: 古江重紀;王 学論
• 通讯作者: 王 学論

Observation of Highly Efficient Spontaneous Emission from Nanostructures Grown on Patterned Substrates

图案化基板上生长的纳米结构高效自发发射的观察

• 发表时间: 2007
• 作者: 古江重紀;王 学論;X. -L. Wang and S. Furue.;X. -L. Wang and S. Furue.;X. -L. Wang and S. Furue.
• 通讯作者: X. -L. Wang and S. Furue.