Abstract
The hole concentration in the strain-compensated B0.14Al0.86N/Al0.5Ga0.5N superlattice (SCSL) is investigated. Compared with the Al0.6Ga0.4N/Al0.5Ga0.5N SL, the effective hole concentration in the SCSL could be improved from 1.1 x 1017 cm-3 to 8.7 x 1018 cm-3 due to the remarkably enlarged valence band bending from 53 meV to 533 meV. We then propose the ultraviolet lightemitting diode (UV LED) structure emitting at 284 nm with the SCSL p-region. Compared with the bulk p-region structure, the UV LED with the SCSL p-region shows improved output characteristics due to the reduced electron leakage and improved hole injection ability. The internal quantum efficiency (IQE) and droop ratio of the SCSL LED structure increases from 49.5% to 54.1% and decreases from 36.8% to 13.6%, respectively. Moreover, the light output powers of the Al0.6Ga0.4N/Al0.5Ga0.5N SL structure and SCSL structure have been improved by 16.3% and 49.1% over the bulk p-region counterpart. Our results indicate that the SCSL structure can be a promising candidate for the high-performance UV LED.