Efficiency droop behavior improvement through barrier thickness modification for GaN-on-silicon light-emitting diodes

Abstract. Crack-free GaN-based light-emitting diodes (LEDs) were grown on 150-mm-diameter Si substrates by using low-pressure metal-organic chemical vapor deposition. The relationship between the LED devices and the thickness of quantum barriers (QBs) was investigated. The crystal quality and surface cracking of GaN-on-Si were greatly improved by an AlxGa1−xN buffer layer composed of graded Al. The threading dislocation density of the GaN-on-Si LEDs was reduced to <7×108  cm−2, yielding LEDs with high internal quantum efficiency. Simulation results indicated that reducing the QB thickness improved the carrier injection rate and distribution, thereby improving the droop behavior of the LEDs. LEDs featuring 6-nm-thick QBs exhibited the lowest droop behavior. However, the experimental results showed an unanticipated phenomenon, namely that the peak external quantum efficiency (EQE) and light output power (LOP) gradually decreased with a decreasing QB thickness. In other words, the GaN-on-Si LEDs with 8-nm-thick QBs exhibited low droop behavior and yielded a good peak EQE and LOP, achieving a 22.9% efficiency droop and 54.6% EQE.

[1]  A. A. Allerman,et al.  Effect of threading dislocations on the Bragg peakwidths of GaN, AlGaN, and AlN heterolayers , 2005 .

[2]  Jing Zhang,et al.  Efficiency-Droop Suppression by Using Large-Bandgap AlGaInN Thin Barrier Layers in InGaN Quantum-Well Light-Emitting Diodes , 2013, IEEE Photonics Journal.

[3]  Yik-Khoon Ee,et al.  III-Nitride Photonics , 2010, IEEE Photonics Journal.

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

[5]  Y. Kuo,et al.  Investigation of Optical Performance of InGaN MQW LED With Thin Last Barrier , 2010, IEEE Photonics Technology Letters.

[6]  H. Xiao,et al.  Effect of AlN buffer thickness on GaN epilayer grown on Si(1 1 1) , 2011 .

[7]  James S. Speck,et al.  Optical properties of yellow light-emitting diodes grown on semipolar (112¯2) bulk GaN substrates , 2008 .

[8]  C. K. Wang,et al.  Investigating the Effect of Piezoelectric Polarization on GaN-Based LEDs With Different Quantum Barrier Thickness , 2013, Journal of Display Technology.

[9]  M. Schubert,et al.  Effect of heterointerface polarization charges and well width upon capture and dwell time for electrons and holes above GaInN/GaN quantum wells , 2010 .

[10]  S. C. Wang,et al.  Erratum: “Reduction of Efficiency Droop in Semipolar (1101) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates” , 2011, CLEO: 2011 - Laser Science to Photonic Applications.

[11]  Nelson Tansu,et al.  Approaches for high internal quantum efficiency green InGaN light-emitting diodes with large overlap quantum wells. , 2011, Optics express.

[12]  E. Schubert,et al.  Effect of Quantum Barrier Thickness in the Multiple-Quantum-Well Active Region of GaInN/GaN Light-Emitting Diodes , 2013, IEEE Photonics Journal.

[13]  S. Nakamura,et al.  InGaN-Based Multi-Quantum-Well-Structure Laser Diodes , 1996 .

[14]  J. Piprek.  Ultra-violet light-emitting diodes with quasi acceptor-free AlGaN polarization doping , 2012 .

[15]  Shuji Nakamura,et al.  Physics of high-power InGaN/GaN lasers , 2002 .

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

[17]  James S. Speck,et al.  High performance thin quantum barrier InGaN/GaN solar cells on sapphire and bulk (0001) GaN substrates , 2013 .

[18]  Hao-Chung Kuo,et al.  Performance of GaN-based light-emitting diodes fabricated using GaN epilayers grown on silicon substrates. , 2014, Optics express.

[19]  S. Denbaars,et al.  High-Power Blue-Violet Semipolar (202̄1̄) InGaN/GaN Light-Emitting Diodes with Low Efficiency Droop at 200 A/cm2 , 2011 .

[20]  N. Tansu,et al.  High-temperature characteristics of Seebeck coefficients for AlInN alloys grown by metalorganic vapor phase epitaxy , 2011 .

[21]  G. Yang,et al.  Influence of strain-induced indium clustering on characteristics of InGaN/GaN multiple quantum wells with high indium composition , 2002 .

[22]  Hongping Zhao,et al.  Analysis of Internal Quantum Efficiency and Current Injection Efficiency in III-Nitride Light-Emitting Diodes , 2013, Journal of Display Technology.

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

[24]  Carrier localization degree of In0.2Ga0.8N/GaN multiple quantum wells grown on vicinal sapphire substrates , 2009 .

[25]  J. Massies,et al.  Barrier-width dependence of group-III nitrides quantum-well transition energies , 1999 .

[26]  M. Craford,et al.  Status and Future of High-Power Light-Emitting Diodes for Solid-State Lighting , 2007, Journal of Display Technology.

[27]  Ronald A. Arif,et al.  Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes , 2010, DRC 2010.

[28]  Chun-Yen Chang,et al.  Electrically driven green, olivine, and amber color nanopyramid light emitting diodes. , 2013, Optics express.

[29]  Hao-Chung Kuo,et al.  Hole injection and electron overflow improvement in InGaN/GaN light-emitting diodes by a tapered AlGaN electron blocking layer. , 2014, Optics express.

[30]  Hongxing Jiang,et al.  Erbium-Doped AlInGaN Alloys as High-Temperature Thermoelectric Materials , 2011 .

[31]  Chih-Wen Liu,et al.  Quasiregular quantum-dot-like structure formation with postgrowth thermal annealing of InGaN/GaN quantum wells , 2002 .

[32]  Manijeh Razeghi,et al.  Surface plasmon enhanced light emission from AlGaN-based ultraviolet light-emitting diodes grown on Si (111) , 2013 .

[33]  E. Schubert,et al.  Analytic model for the efficiency droop in semiconductors with asymmetric carrier-transport properties based on drift-induced reduction of injection efficiency , 2012 .

[34]  H. Choi,et al.  Effects of enhanced lateral transport on InGaN/GaN light emitting diodes via n-type AlGaN/GaN superlattices , 2013 .

[35]  Jerry R. Meyer,et al.  Band parameters for nitrogen-containing semiconductors , 2003 .