Effects of lateral current injection in GaN multi-quantum well light-emitting diodes

In conventional multi-quantum well (MQW) LEDs, typically only one QW emits light due to a very nonuniform carrier distribution. We show by numerical simulations that by adopting a genuinely two-dimensional LED structure enabling lateral hole current injection into the QWs it becomes possible to achieve a more even carrier distribution potentially enabling smaller droop and uniform light emission from all the QWs in the MQW stack. We also show that the uneven emission may be explained with standard current transport models as quasi-Fermi losses between successive quantum wells. We demonstrate our findings by studying three different LED structures and comparing our results to published experimental results.

[1]  Christiane Poblenz,et al.  Measurement of polarization charge and conduction-band offset at InxGa1−xN/GaN heterojunction interfaces , 2004 .

[2]  Enrico Bellotti,et al.  Transport Parameters of Electrons and Holes , 2007 .

[3]  J.-W. Shi,et al.  Phosphor-Free GaN-Based Transverse Junction White-Light Light-Emitting Diodes With Regrown n-Type Regions , 2008, IEEE Photonics Technology Letters.

[4]  Hadis Morkoç,et al.  Reduction of efficiency droop in InGaN light emitting diodes by coupled quantum wells , 2008 .

[5]  E. Fred Schubert,et al.  Reduction in efficiency droop, forward voltage, ideality factor, and wavelength shift in polarization-matched GaInN/GaInN multi-quantum-well light-emitting diodes , 2009 .

[6]  A. Carlo,et al.  EFFECTS OF MACROSCOPIC POLARIZATION IN III-V NITRIDE MULTIPLE QUANTUM WELLS , 1999, cond-mat/9905186.

[7]  Miao-Chan Tsai,et al.  Effect of polarization state on optical properties of blue-violet InGaN light-emitting diodes , 2010 .

[8]  Alexander I. Zhmakin,et al.  Simulation of visible and ultra-violet group-III nitride light emitting diodes , 2006, J. Comput. Phys..

[9]  Andrea L. Lacaita,et al.  Quantum-corrected drift-diffusion models for transport in semiconductor devices , 2005 .

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

[11]  David Vanderbilt,et al.  Spontaneous polarization and piezoelectric constants of III-V nitrides , 1997 .

[12]  Hao-Chung Kuo,et al.  Low efficiency droop in blue-green m-plane InGaN/GaN light emitting diodes , 2010 .

[13]  Dong-Yul Lee,et al.  Effect of electron blocking layer on efficiency droop in InGaN/GaN multiple quantum well light-emitting diodes , 2009 .

[14]  J. Chyi,et al.  The Structure of GaN-Based Transverse Junction Blue LED Array for Uniform Distribution of Injected Current/Carriers , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[15]  Yen-Kuang Kuo,et al.  Numerical simulation of blue InGaN light-emitting diodes with polarization-matched AlGaInN electron-blocking layer and barrier layer , 2009 .

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

[17]  S. Karpov.  Visible Light‐Emitting Diodes , 2007 .

[18]  Hao-Chung Kuo,et al.  Investigation of wavelength-dependent efficiency droop in InGaN light-emitting diodes , 2010 .

[19]  P. Han,et al.  A thermodynamic model and estimation of the experimental value of spontaneous polarization in a wurtzite GaN , 2009 .

[20]  Paul S. Martin,et al.  High performance thin-film flip-chip InGaN–GaN light-emitting diodes , 2006 .

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

[22]  Yen-Kuang Kuo,et al.  Improvement in output power of a 460 nm InGaN light-emitting diode using staggered quantum well , 2010 .

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

[24]  D. Biswas,et al.  Band offsets of InXGa1−XN/GaN quantum wells reestimated , 2007 .

[25]  F. Bernardini,et al.  First-principles prediction of structure, energetics, formation enthalpy, elastic constants, polarization, and piezoelectric constants of AlN, GaN, and InN: Comparison of local and gradient-corrected density-functional theory , 2001 .

[26]  Jani Oksanen,et al.  The challenge of unity wall plug efficiency: The effects of internal heating on the efficiency of light emitting diodes , 2010 .