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We investigate the performances of the near-ultraviolet(about 350 nm-360 nm) light-emitting diodes(LEDs) each with specifically designed irregular sawtooth electron blocking layer(EBL) by using the APSYS simulation program.The internal quantum efficiencies(IQEs),light output powers,carrier concentrations in the quantum wells,energy-band diagrams,and electrostatic fields are analyzed carefully.The results indicate that the LEDs with composition-graded pAl_xGa_(1-x)N irregular sawtooth EBLs have better performances than their counterparts with stationary component p-AlGaN EBLs.The improvements can be attributed to the improved polarization field in EBL and active region as well as the alleviation of band bending in the EBL/p-AlGaN interface,which results in less electron leakage and better hole injection efficiency,thus reducing efficiency droop and enhancing the radiative recombination rate.
We investigate the performances of the near-ultraviolet (about 350 nm-360 nm) light-emitting diodes (LEDs) each with a specifically designed irregular sawtooth electron blocking layer (EBL) by using the APSYS simulation program.The internal quantum efficiencies (IQEs) , light output powers, carrier concentrations in the quantum wells, energy-band diagrams, and electrostatic fields are analyzed carefully. The results that indicate that the LEDs with composition-graded pAl_xGa_ (1-x) N irregular sawtooth EBLs have better performances than their counterparts with stationary component p-AlGaN EBLs.The improvements can be attributed to the improved polarization field in EBL and active region as well as the alleviation of band bending in the EBL / p-AlGaN interface, which results in less electron leakage and better hole injection efficiency, reduced reducing droop and enhancing the radiative recombination rate.