Emission enhancement in GaN-based light emitting diodes with shallow triangular quantum wells

GaN-based light emitting diodes (LEDs) with shallow triangular quantum wells (TQW) structure were proposed and investigated. LEDs with shallow TQW demonstrated a lower turn-on voltage and 80% higher lighting efficiency at 20 mA than devices without the shallow QW structure. A more stable emission wavelength and a lower ideality factor were achieved with the proposed structure. X-ray reciprocal space mapping revealed a partial strain relaxation in active region due to the insertion of the TQW structure. The improved performance is ascribed to the weakening of the polarization field in the MQW active region induced by the TQW structure.

[1]  Jong Kyu Kim,et al.  Solid-State Light Sources Getting Smart , 2005, Science.

[2]  Y. T. Rebane,et al.  Light Emitting Diode with Charge Asymmetric Resonance Tunneling , 2000 .

[3]  Chih-Min Chuang,et al.  Piezoelectric effects in the optical properties of strained InGaN quantum wells , 1999 .

[4]  G. Jung,et al.  Effects of Patterned Sapphire Substrates on Piezoelectric Field in Blue-Emitting InGaN Multiple Quantum Wells , 2010, IEEE Electron Device Letters.

[5]  Nitride-Based Dual-Stage MQW LEDs , 2007 .

[6]  S. Nakamura,et al.  Spontaneous emission of localized excitons in InGaN single and multiquantum well structures , 1996 .

[7]  Gang Wang,et al.  Contrary luminescence behaviors of InGaN/GaN light emitting diodes caused by carrier tunneling leakage , 2011 .

[8]  E. Suh,et al.  Efficient blue light-emitting diodes with InGaN/GaN triangular shaped multiple quantum wells , 2003 .

[9]  Isamu Akasaki,et al.  Quantum-Confined Stark Effect due to Piezoelectric Fields in GaInN Strained Quantum Wells , 1997 .

[10]  E. Fred Schubert,et al.  The origin of the high diode-ideality factors in GaInN/GaN multiple quantum well light-emitting diodes , 2009 .

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

[12]  James S. Speck,et al.  Nonpolar InGaN∕GaN emitters on reduced-defect lateral epitaxially overgrown a-plane GaN with drive-current-independent electroluminescence emission peak , 2004 .

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

[14]  Hao-Chung Kuo,et al.  Study of the Excitation Power Dependent Internal Quantum Efficiency in InGaN/GaN LEDs Grown on Patterned Sapphire Substrate , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

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

[16]  Z. J. Yang,et al.  Analysis of optical gain property in the InGaN/GaN triangular shaped quantum well under the piezoelectric field , 2009 .