Efficiency Improvement of Blue LEDs Using a GaN Burried Air Void Photonic Crystal With High Air Filling Fraction

In this paper, we investigate the efficiency enhancement of blue InGaN/GaN light-emitting diodes (LEDs) by incorporating a burried air void photonic crystal (BAVPC) layer within the epitaxial structure. As compared with the conventional patterned sapphire substrate (C-PSS) LEDs and flat sapphire substrate LEDs with BAVPC, the fabricated patterned sapphire substrate (PSS) LEDs with BAVPC exhibit the lowest full-width at half-maximum of (002) and (102) diffraction peaks, the highest light output power of 20.6 mW, and the highest external quantum efficiency of 37.4%. Remarkable performance improvement in the PSS LED with BAVPC is attributed to the better epitaxial quality with threading dislocations terminated by the BAVPC and the higher scattering at interface between GaN and air-void. By positioning the BAVPC directly below the multiple quantum wells (MQWs), it would cause the reduction in the number of trapped optical modes. The methodology optically isolates the MQWs from the underlying substrate and increases the optical output power. Moreover, threading dislocations are significantly suppressed using the BAVPC with high air filling fraction of ~ 50%. It is well proposed that this methodology provides a promising alternative to C-PSS LEDs.

[1]  Efficiency Improvement of Near-Ultraviolet Nitride-Based Light-Emitting-Diode Prepared on GaN Nano-Rod Arrays by Metalorganic Chemical Vapor Deposition , 2014, IEEE Journal of Quantum Electronics.

[2]  Martin D. B. Charlton,et al.  Optimisation of pattern geometry and investigations of physical mechanisms contributing to improved light extraction in patterned substrate LEDs , 2011, OPTO.

[3]  Improved Light Output Power of GaN-Based Light-Emitting Diodes Using Double Photonic Quasi-Crystal Patterns , 2009, IEEE Electron Device Letters.

[4]  Yi’an Yin,et al.  Performance enhancement of blue light-emitting diodes with a special designed AlGaN/GaN superlattice electron-blocking layer , 2011 .

[5]  JianJang Huang,et al.  Application of Nanosphere Lithography to LED Surface Texturing and to the Fabrication of Nanorod LED Arrays , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[6]  F. Kong,et al.  Improving Light Extraction Efficiency of GaN-Based LEDs by Al$_{\bm x}$Ga$_{{\bf 1}{\bm -}{\bm x}}$N Confining Layer and Embedded Photonic Crystals , 2012, IEEE Journal of Selected Topics in Quantum Electronics.

[7]  Thierry Pauporté,et al.  Low‐Voltage UV‐Electroluminescence from ZnO‐Nanowire Array/p‐GaN Light‐Emitting Diodes , 2010, Advanced materials.

[8]  C. S. Oh,et al.  Effects of growth rate of a GaN buffer layer on the properties of GaN on a sapphire substrate , 1999 .

[9]  Y. Moon,et al.  Light emission enhancement in blue InGaAlN/InGaN quantum well structures , 2011 .

[10]  I. Hwang,et al.  Design Optimization of Photonic Crystal Structure for Improved Light Extraction of GaN LED , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[11]  S.J. Chang,et al.  High efficiency and improved ESD characteristics of GaN-based LEDs with naturally textured surface grown by MOCVD , 2006, IEEE Photonics Technology Letters.

[12]  P. Bhattacharya,et al.  Auger recombination in III-nitride nanowires and its effect on nanowire light-emitting diode characteristics. , 2011, Nano letters.

[13]  A. Uedono,et al.  Origin of defect-insensitive emission probability in In-containing (Al,In,Ga)N alloy semiconductors , 2006, Nature materials.

[14]  Takashi Mukai,et al.  Ultraviolet InGaN and GaN Single-Quantum-Well-Structure Light-Emitting Diodes Grown on Epitaxially Laterally Overgrown GaN Substrates , 1999 .

[15]  Je-Hyung Kim,et al.  Electrically Driven Quantum Dot/Wire/Well Hybrid Light‐Emitting Diodes , 2011, Advanced materials.

[16]  M. Charlton,et al.  Effect of coalescence layer thickness on the properties of thin‐chip InGaN/GaN light emitting diodes with embedded photonic quasi‐crystal structures , 2012 .

[17]  Taeil Jung,et al.  Novel Epitaxial Nanostructures for the Improvement of InGaN LEDs Efficiency , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[18]  Buem Joon Kim,et al.  Design Rule of Nanostructures in Light‐Emitting Diodes for Complete Elimination of Total Internal Reflection , 2012, Advanced materials.

[19]  Hao-Chung Kuo,et al.  High efficiency GaN-based light-emitting diodes with embedded air voids/SiO2 nanomasks , 2012, 2012 Conference on Lasers and Electro-Optics (CLEO).

[20]  M. Charlton,et al.  Enhanced Light Extraction by Photonic Quasi-Crystals in GaN Blue LEDs , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[21]  Seong-Ju Park,et al.  Improvement of efficiency droop in InGaN/GaN multiple quantum well light-emitting diodes with trapezoidal wells , 2010 .

[22]  Hao-Chung Kuo,et al.  Highly Efficient and Bright LEDs Overgrown on GaN Nanopillar Substrates , 2011, IEEE Journal of Selected Topics in Quantum Electronics.

[23]  Enhancement in light extraction of LEDs with SiO2 current blocking layer deposited on naturally textured p-GaN surface , 2013 .

[24]  H. Kuo,et al.  Efficiency Improvement of GaN-Based LEDs With a $ \hbox{SiO}_{2}$ Nanorod Array and a Patterned Sapphire Substrate , 2010, IEEE Electron Device Letters.

[25]  Z. Z. Chen,et al.  Evolution and control of dislocations in GaN grown on cone-patterned sapphire substrate by Metal Organic Vapor PhaseEpitaxy , 2011 .

[26]  W. Lai,et al.  Nitride-based LEDs with textured side walls , 2004, IEEE Photonics Technology Letters.

[27]  Tae Geun Kim,et al.  Effects of Nanometer-Scale Photonic Crystal Structures on the Light Extraction From GaN Light-Emitting Diodes , 2010, IEEE Journal of Quantum Electronics.

[28]  I. Ferguson,et al.  Air-voids embedded high efficiency InGaN-light emitting diode , 2008 .

[29]  James S. Speck,et al.  Role of threading dislocation structure on the x‐ray diffraction peak widths in epitaxial GaN films , 1996 .

[30]  D. Allsopp,et al.  Light Extracting Properties of Buried Photonic Quasi-Crystal Slabs in InGaN/GaN LEDs , 2013, Journal of Display Technology.

[31]  Yun-Li Li,et al.  Growth Mechanism and Strain Variation of GaN Material Grown on Patterned Sapphire Substrates With Various Pattern Designs , 2011, IEEE Photonics Technology Letters.

[32]  Martin D. B. Charlton,et al.  High-efficiency photonic quasi-crystal light emitting diodes incorporating buried photonic crystal structures , 2010, Optical Engineering + Applications.

[33]  Eli Yablonovitch,et al.  Light extraction from optically pumped light-emitting diode by thin-slab photonic crystals , 1999 .