Novel 2D/3D Heterojunction for UV Light-Emitting Diodes Using Hexagonal Boron Nitride as Hole Injection Layer

Abstract

The AlGaN materials system has been extensively studied in order to improve the efficiency of UV-B and UV-C light-emitting diodes (LEDs). While progress has been made, significant challenges remain at shorter wavelengths. Most notably, increased Al composition for shorter-wavelength operation results in increased activation energy of Mg dopants, resulting in low p-doping. Although p-doped h-BN, with a bandgap of 5.9 eV, has been proposed as a potential replacement of p-doped AlGaN, there have not been demonstrations of LEDs fabricated from p-doped h-BN/AlGaN heterostructures. Such unique heterostructures combine 2D p-doped h-BN materials with 3D AlGaN materials. Herein, fabrication and characterization of p-doped h-BN/AlGaN multiple quantum wells (MQWs)/n-AlGaN LEDs, demonstrating emission of light at 290 nm corresponding to the AlGaN MQWs, with weaker emission at 262 nm corresponding to the AlGaN barrier, are reported. These results conclusively show hole injection through p-doped h-BN into AlGaN and provide a proof of concept that p-doped h-BN can be an alternative hole injection layer for UV LEDs.