Optimization on the luminous efficiency in AlGaN-based ultraviolet light-emitting diodes by amendment of a superlattice hole reservoir layer

Deep Ultraviolet AlGaN-Based Light-Emitting Diodes with p-AlGaN/AlGaN Superlattice Hole Injection Structures

“…This effect could result in the enhancement of the light output power of the DUV LEDs. Mondal et al [11] and Yang et al [12] have reported simulation results for similar DUV LED structures. They concluded that after the EBL of DUV LEDs, SLs or multilayer p-AlGaN/AlGaN structures effectively increased hole injection in the MQW region to enhance the light output power of the DUV In addition to their reduced V f and dynamic resistance, the DUV LEDs with the proposed p-Al 0.8 Ga 0.2 N/Al 0.48 Ga 0.52 N SL hole injection layer exhibited reduced current at applied voltages less than 3 V compared with the reference LEDs.…”

“…This effect could result in the enhancement of the light output power of the DUV LEDs. Mondal et al [11] and Yang et al [12] have reported simulation results for similar DUV LED structures. They concluded that after the EBL of DUV LEDs, SLs or multilayer p-AlGaN/AlGaN structures effectively increased hole injection in the MQW region to enhance the light output power of the DUV LEDs.…”

“…Despite the dramatic improvements in DUV LED performance, AlGaN-based DUV LEDs continue to face the problems of high-defect density and low-hole concentrations of high Al-content AlGaN material. Since the initial study on GaN-based LEDs, the low-hole concentrations of p-type GaN-based material has been a major issue that limits the efficiency of GaN-based LEDs because it causes poor hole injection [12][13][14][15][16][17]. Moreover, the problem of low-hole concentration for p-type Al x Ga 1−x N with x > 0.5 is worsening [10][11][12][13].…”

“…Since the initial study on GaN-based LEDs, the low-hole concentrations of p-type GaN-based material has been a major issue that limits the efficiency of GaN-based LEDs because it causes poor hole injection [12][13][14][15][16][17]. Moreover, the problem of low-hole concentration for p-type Al x Ga 1−x N with x > 0.5 is worsening [10][11][12][13]. The doping efficiency for AlGaN with high Al content is still far from satisfactory due to a combination of factors involving limited solubility, high activation energy, increased donor compensations, and increased hole scatterings [14,15].…”

AlGaN-Based Deep Ultraviolet Light-Emitting Diodes with Thermally Oxidized AlxGa2–xO3 Sidewalls

“… 16 Many studies proposed Mg-doped Al(In)GaN/Al(In)GaN superlattice structure to replace the electron blocking layer (EBL) to deal with low carrier confinement and hole injection issues. 15 , 17 − 22 This method can effectively increase the hole concentration and band offset of EBL to improve hole injection and electron confinement. In addition to EBL with an Al(In)GaN/Al(In)GaN superlattice structure, the use of the wide band gap interlayer, 23 serrated p-AlGaN region, 24 and step 25 and linear 26 , 27 grading profiles of p-AlGaN was proposed to replace traditional p-AlGaN EBL.…”