Improved performance of near UV light-emitting diodes with a composition-graded p-AlGaN irregular sawtooth electron-blocking layer

Qin, Ping; Song, Weidong; Hu, Wenxiao; Zhang, Yuanwen; Zhang, Chongzhen; Wang, Ru-Peng; Zhao, Lingling; Xia, Chao; Yuan, Songyang; Yin, Yongsheng; Li, Shuti; Su, Shichen

doi:10.1088/1674-1056/25/8/088505

Cited by 14 publications

(4 citation statements)

References 29 publications

(25 reference statements)

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“…Late Akasaki et al have reduce threshold current density by improving optical confinement factor and carrier injection efficiency of AlGaN ultraviolet semiconductor lasers [ 14 , 15 ]. Various electron-blocking layers have also been introduced to reduce electron leakage and improve hole injection efficiency [ 16 – 18 ]. However, little research has been done on the cladding layers of LD.…”

Section: Introductionmentioning

confidence: 99%

Performance improvement of nitride semiconductor-based deep-ultraviolet laser diodes with superlattice cladding layers

Zhang

et al. 2022

Eur. Phys. J. D

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A deep-ultraviolet (DUV) laser diode (LD) consisting of specifically designed cladding layers involving superlattice nitride alloy has been proposed. Simulation studies of different cladding layers were carried out using Crosslight software. It was found that the proposed structure effectively suppresses the leakage of the optical field from the active region and the optical confinement coefficient is 1.45 times higher than that of the conventional structure. The proposed structure has a significant increase in laser power with a low threshold current. Moreover, the introduction of novel cladding layer suppresses the electron and hole leakage from the multiple quantum well (MQW) region, which provides an attractive solution for increasing the stimulated recombination rate in the MQW region leading to the improvement in the performance of the DUV LD. Graphical abstract

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Section: Introductionmentioning

confidence: 99%

Performance improvement of nitride semiconductor-based deep-ultraviolet laser diodes with superlattice cladding layers

Zhang

et al. 2022

Eur. Phys. J. D

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“…Through this, the uneven distribution of carriers occurs, which further stymies the AlGaN-based DUV LEDs performance [ 17 ]. To tackle this issue, many sophisticated approaches have been used such as V-shaped EBL [ 18 ], W-shaped EBL [ 19 ], irregular sawtooth EBL [ 20 ], trapezoidal EBL [ 21 ], and anti-trapezoidal EBL [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

The marvelous optical performance of AlGaN-based deep ultraviolet light-emitting diodes with AlInGaN-based last quantum barrier and step electron blocking layer

et al. 2021

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The optoelectronic characteristics of AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with quaternary last quantum barrier (QLQB) and step-graded electron blocking layer (EBL) are investigated numerically. The results show that the internal quantum efficiency (IQE) and radiative recombination rate are remarkably improved with AlInGaN step-graded EBL and QLQB as compared to conventional or ternary AlGaN EBL and last quantum barrier (LQB). This significant improvement is assigned to the optimal recombination of electron–hole pairs in the multiple quantum wells (MQWs). It is due to the decrease in strain and lattice mismatch between the epi-layers which alleviates the effective potential barrier height of the conduction band and suppressed the electron leakage without affecting the holes transportation to the active region. Moreover, to figure out quantitatively, the electron and hole quantity increased by ~ 25% and ~ 15%, respectively. Additionally, the IQE and radiative recombination rate are enhanced by 48% and 55%, respectively, as compared to conventional LED. So, we believe that our proposed structure is not only a feasible approach for achieving highly efficient DUV LEDs, but the device physics presented in this study establishes a fruitful understanding of III nitride-based optoelectronic devices.

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“…In addition, the UV LEDs also face the problem of efficiency droop, the IQE of the UV LEDs obviously decreases at high current, which further restricts the commercial application of the UV LEDs. Some methods have been proposed to solve the above problems, such as adopting polarization-induced hole doping to enhance the hole concentration in p-type AlGaN, [5] designing a special electron blocking layer (EBL) to reduce electron leakage, [6][7][8] proposing special quantum well structures to depress the polarization effect in the active region. [9] In UV LEDs, a high Al content p-type AlGaN EBL is normally used to enhance the restriction of electrons and reduce electron leakage to the ptype layer.…”

Section: Introductionmentioning

confidence: 99%

Enhanced performance of AlGaN-based ultraviolet light-emitting diodes with linearly graded AlGaN inserting layer in electron blocking layer*

Wang

Song

et al. 2019

Chinese Phys. B

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The conventional stationary Al content AlGaN electron blocking layer (EBL) in ultraviolet light-emitting diode (UV LED) is optimized by employing a linearly graded AlGaN inserting layer which is 2.0 nm Al0.3Ga0.7N/5.0 nm Al x Ga1−x N/8.0 nm Al0.3Ga0.7N with decreasing value of x. The results indicate that the internal quantum efficiency is significantly improved and the efficiency droop is mitigated by using the proposed structure. These improvements are attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes, which result in an increased hole injection efficiency and a decreased electron leakage into the p-type region. In addition, the linearly graded AlGaN inserting layer can generate more holes in EBL due to the polarization-induced hole doping and a tunneling effect probably occurs to enhance the hole transportation to the active regions, which will be beneficial to the radiative recombination.

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Improved performance of near UV light-emitting diodes with a composition-graded p-AlGaN irregular sawtooth electron-blocking layer

Cited by 14 publications

References 29 publications

Performance improvement of nitride semiconductor-based deep-ultraviolet laser diodes with superlattice cladding layers

Performance improvement of nitride semiconductor-based deep-ultraviolet laser diodes with superlattice cladding layers

The marvelous optical performance of AlGaN-based deep ultraviolet light-emitting diodes with AlInGaN-based last quantum barrier and step electron blocking layer

Enhanced performance of AlGaN-based ultraviolet light-emitting diodes with linearly graded AlGaN inserting layer in electron blocking layer*

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