BAlN for III-nitride UV light-emitting diodes: undoped electron blocking layer

Abstract

The undoped BAlN electron-blocking layer (EBL) is investigated to replace the conventional AlGaN EBL in light-emitting diodes (LEDs). Numerical studies of the impact of variously doped EBLs on the output characteristics of LEDs demonstrate that the LED performance shows heavy dependence on the p-doping level in the case of the AlGaN EBL, while it shows less dependence on the p-doping level for the BAlN EBL. As a result, we propose an undoped BAlN EBL for LEDs to avoid the p-doping issues, which a major technical challenge in the AlGaN EBL. Without doping, the proposed BAlN EBL structure still possesses a superior capacity in blocking electrons and improving hole injection compared with the AlGaN EBL having high doping. Compared with the Al0.3Ga0.7N EBL with a doping concentration of 1 × 1020 cm−3, the undoped BAlN EBL LED still shows lower droop (only 5%), compatible internal quantum efficiency (2% enhancement), and optical output power (6% enhancement). This study provides a feasible route to addressing electron leakage and insufficient hole injection issues when designing ultraviolet LED structures.

Morphology and carrier mobility of high-B-content BxAl1−xN ternary alloys from an ab initio global search

“…B x Al 1− x N is highly expected to be useful when applied in the undoped electron-blocking layer (EBL) to overcome the p-doping problem in Al x Ga 1− x N. 17 Therefore, the carrier mobility is quite important to the performance. However, there is a lack of reports on this for B x Al 1− x N alloys.…”

“…7–13 Replacing the cation with boron, the lightest element of the IIIA group, can also increase the flexibility of applications. 14–17 The B x Al 1− x N/AlN superlattice would enable a high density of two-dimensional electron gas (2DEG) in its layers 14 since wurtzite boron nitride (w-BN) possesses the strongest spontaneous polarization of 2.174 C m −2 (ref. 18 and 19) in III-nitrides.…”

“…15,16 Undoped B x Al 1− x N can also replace the conventional Al 1− x Ga x N in the electron-blocking layer (EBL) in LEDs, which suffers from p-doping problems. 17 However, there are the following two difficulties in alloying boron compared with other III-nitrides:…”

53‐1: Invited Paper: Enhanced Performance of III‐Nitride‐Based Light‐Emitting Diodes Through Novel Band Engineering and Fabrication Technology

“…Therefore, the high-Al content electron blocking layer can be removed from the LED structure without performance degradation. Besides, we reported a highperformance UV LED with a BAlN EBL [7]. BAlN is an emerging ultra-wide bandgap III-Nitride semiconductor.…”

A machine learning study on superlattice electron blocking layer design for AlGaN deep ultraviolet light-emitting diodes using the stacked XGBoost/LightGBM algorithm

“…10 The energy band can also be modulated by employing various materials and structures. Wen et al proposed an undoped B 0.14 Al 0.86 N EBL to significantly improve electron blocking and hole injection, 11 and Liu et al used InAlN as the LQB to modulate the polarization charge and band bending at the LQB/EBL. 12 Ren et al revealed that the EBL could be removed in DUV LEDs using a composition-grade quantum barrier.…”