On the hole accelerator for III-nitride light-emitting diodes

Abstract

In this work, we systematically conduct parametric studies revealing the sensitivity of the hole injection on the hole accelerator (a hole accelerator is made of the polarization mismatched p-electron blocking layer (EBL)/p-GaN/p-AlxGa1−xN heterojunction) with different designs, including the AlN composition in the p-AlxGa1−xN layer, and the thickness for the p-GaN layer and the p-AlxGa1−xN layer. According to our findings, the energy that the holes obtain does not monotonically increase as the AlN incorporation in the p-AlxGa1−xN layer increases. Meanwhile, with p-GaN layer or p-AlxGa1−xN layer thickening, the energy that the holes gain increases and then reaches a saturation level. Thus, the hole injection efficiency and the device efficiency are very sensitive to the p-EBL/p-GaN/p-AlxGa1−xN design, and the hole accelerator can effectively increase the hole injection if properly designed.

Numerical Investigations on the n+‐GaN/AlGaN/p+‐GaN Tunnel Junction for III‐Nitride UV Light‐Emitting Diodes

“…The electron injection efficiency can be improved by reducing the kinetic energy for electrons, increasing the effective conduction band barrier height for the quantum barriers, reducing the electron accumulation level between the last quantum barrier, and the p‐type electron blocking layer (p‐EBL) . Nevertheless, on the contrary to the design strategy for electrons, to improve the hole injection efficiency, we have to make holes “hot” and/or decrease the valence band barrier height both in the active region and in the p‐EBL for the holes. Aside from increasing the hole injection by playing with the inner layers for the LEDs, the hole injection efficiency is also strongly influenced by the p‐type contact layer, as the result of which a metal/insulator/semiconductor structured charge inverter is proposed to reduce the tunnel region width within the p‐type contact layer and then promotes the hole transport from the p‐type contact metal into the device .…”

On the Hole Injection for III-Nitride Based Deep Ultraviolet Light-Emitting Diodes

“…By following , the work ( W ) that the holes obtain can be calculated (see Table 1 ). Here e , l and E field represent the unit electronic charge, the integration range and the electric field within the integration range [ 73 , 74 ]. Figure 6 c also shows that the p-Al x Ga 1− x N layer is fully depleted for the Reference device and Device 1 (D1), and therefore the electric field intensity is very strong which produces an extremely large energy for holes (see Table 1 ).…”

Enhancing Efficiency of AlGaN Ultraviolet‐B Light‐Emitting Diodes with Graded p‐AlGaN Hole Injection Layer

“…[ 18 ] However, it is difficult to further reduce the Mg doping concentration as the Mg doping efficiency is already very low for the Al‐rich AlGaN layers. By considering this limitation and to energize the holes, an electric field reservoir [ 19 ] and hole accelerator layers [ 20 ] are proposed, and the advantage of the polarization‐induced electric field is taken into account.…”