Achieving High-Performance Blue GaN-Based Light-Emitting Diodes by Energy Band Modification on AlxInyGa1–x–yN Electron Blocking Layer

We have achieved high-performance blue GaN-based light-emitting diodes (LEDs) by energy band modification on an Al<sub><italic>x</italic></sub>In<sub><italic>y</italic></sub>Ga<sub>1–<italic>x</italic>–<italic>y</italic></sub>N electron blocking layer (EBL). It is demonstrated by simulation that the strategy using high In/Al ratio to decrease polarization charge density and to alleviate the negative effect from polarization electric fields is more favorable. Using the optimal In/Al ratio of 0.5, the LED with Al<sub>0.40</sub>In<sub>0.20</sub>Ga<sub>0.40</sub>N EBL shows a comprehensive performance improvement. With comparison to the LED with conventional Al<sub>0.15</sub>GaN<sub>0.85</sub>N EBL, such an LED owns a 270.15% improvement on the simulated luminous intensity and shows the smallest voltage of 3.34 V at 100 A/cm<sup>2</sup>. The subsequent experimental results provide the evidence to the superiority of Al<sub><italic>x</italic></sub>In<sub><italic>y</italic></sub>Ga<sub>1–<italic>x</italic>–<italic>y</italic></sub>N<sub>1–<italic>x</italic>–<italic>y</italic></sub>N EBL with a high In/Al ratio. Compared with the reference LED with Al<sub>0.15</sub>Ga<sub>0.85</sub>N EBL, the experimental light output power of the LED with Al<sub>0.35</sub>In<sub>0.18</sub>Ga<sub>0.47</sub>N EBL is 86.58 mW, achieving the best improvement by 31.38%. And the voltage of this LED at 14.4 A/cm<sup>2</sup> (20 mA) is 3.35 V, which is much smaller than the voltage of 3.45 V for the reference LED. Evidently, the Al<sub><italic>x</italic></sub>In<sub><italic>y</italic></sub>Ga<sub>1–<italic>x</italic>–<italic>y</italic></sub>N EBL with the In/Al ratio of 0.5 is very effective to promote the performance of LED, which is very promising to be applied in the further high-performance LED fabrication.

[1]  Shuji Nakamura,et al.  History of Gallium–Nitride-Based Light-Emitting Diodes for Illumination , 2013, Proceedings of the IEEE.

[2]  Joachim Piprek,et al.  How to decide between competing efficiency droop models for GaN-based light-emitting diodes , 2015 .

[3]  Wenliang Wang,et al.  Epitaxial growth of group III-nitride films by pulsed laser deposition and their use in the development of LED devices , 2015 .

[4]  Growth temperature effect on the optical and material properties of AlxInyGa1-x-yN epilayers grown by MOCVD , 2003 .

[5]  Wenliang Wang,et al.  GaN-based light-emitting diodes on various substrates: a critical review , 2016, Reports on progress in physics. Physical Society.

[6]  Salah M. Bedair,et al.  High optical quality AlInGaN by metalorganic chemical vapor deposition , 1999 .

[7]  S. Lepkowski,et al.  Anomalous composition dependence of the band gap pressure coefficients in In-containing nitride semiconductors , 2010 .

[8]  Oliver Ambacher,et al.  Evidence for nonlinear macroscopic polarization in III-V nitride alloy heterostructures , 2002 .

[9]  Wei Liu,et al.  On the origin of the electron blocking effect by an n-type AlGaN electron blocking layer , 2014 .

[10]  T. Suski,et al.  Band gap bowing in quaternary nitride semiconducting alloys , 2011 .

[11]  T. Suski,et al.  Influence of indium clustering on the band structure of semiconducting ternary and quaternary nitride alloys , 2009 .

[12]  Su-Huai Wei,et al.  Effects of the Wave Function Localization in AlInGaN Quaternary Alloys , 2007 .

[13]  J. Piprek,et al.  Sensitivity analysis of electron leakage in III-nitride light-emitting diodes , 2013 .

[14]  Shuqi Chen,et al.  Employing low-temperature barriers to achieve strain-relaxed and high-performance GaN-based LEDs. , 2016, Optics express.

[15]  John C. Roberts,et al.  Growth and characterization of AlInGaN quaternary alloys , 1996 .

[16]  S. Inoue,et al.  Enhanced wall-plug efficiency in AlGaN-based deep-ultraviolet light-emitting diodes with uniform current spreading p-electrode structures , 2016 .

[17]  Heqing Wang,et al.  Barrier effect on hole transport and carrier distribution in InGaN∕GaN multiple quantum well visible light-emitting diodes , 2008 .

[18]  H. Kuo,et al.  Effects of Built-In Polarization and Carrier Overflow on InGaN Quantum-Well Lasers With Electronic Blocking Layers , 2008, Journal of Lightwave Technology.

[19]  T. Hsu,et al.  Effect of N-Type AlGaN Layer on Carrier Transportation and Efficiency Droop of Blue InGaN Light-Emitting Diodes , 2009, IEEE Photonics Technology Letters.

[20]  R. Martin,et al.  Composition and luminescence of AlInGaN layers grown by plasma-assisted molecular beam epitaxy , 2008 .

[21]  M. Shur,et al.  Energy Band/Lattice Mismatch Engineering in Quaternary AlInGaN/GaN Heterostructure , 1999 .

[22]  G. Fan,et al.  Numerical simulation of blue InGaN light-emitting diode with gradual Al and In composition p-AlInGaN electron-blocking layer , 2015, Journal of Materials Science: Materials in Electronics.

[23]  E. Schubert.  Light-Emitting Diodes: Frontmatter , 2006 .

[24]  J. Piprek.  Efficiency droop in nitride‐based light‐emitting diodes , 2010 .

[25]  Tae Geun Kim,et al.  Improved light output power in GaN-based vertical light-emitting diodes with p-AlInGaN/GaN superlattices , 2012 .

[26]  E. Schubert.  Light-Emitting Diodes by E. Fred Schubert , 2006 .

[27]  B. Lin,et al.  Polarization-matched quaternary superlattice electron blocking layer in blue InGaN light-emitting diodes , 2016 .

[28]  Manish Mathew,et al.  Droop-multimode trade-off in GaN-InGaN LEDs: Effect of polarization-matched AlInGaN blocking layers , 2015 .

[29]  Michael R. Krames,et al.  Carrier distribution in (0001)InGaN∕GaN multiple quantum well light-emitting diodes , 2008 .

[30]  Bo Monemar,et al.  Fundamental energy gap of GaN from photoluminescence excitation spectra , 1974 .

[31]  E. Fred Schubert,et al.  Origin of efficiency droop in GaN-based light-emitting diodes , 2007 .

[32]  Joachim Piprek,et al.  Electron leakage effects on GaN-based light-emitting diodes , 2010 .

[33]  Jerry R. Meyer,et al.  Band parameters for III–V compound semiconductors and their alloys , 2001 .

[34]  G. Verzellesi,et al.  Efficiency droop in InGaN/GaN blue light-emitting diodes: Physical mechanisms and remedies , 2013 .