Electrical and optical characteristics of highly transparent MOVPE-grown AlGaN-based tunnel heterojunction LEDs emitting at 232 nm

We present the growth and electro-optical characteristics of highly transparent AlGaN-based tunnel heterojunction light-emitting diodes (LEDs) emitting at 232 nm entirely grown by metalorganic vapor phase epitaxy (MOVPE). A GaN:Si interlayer was embedded into a highly Mg- and Si-doped Al0.87Ga0.13N tunnel junction to enable polarization field enhanced tunneling. The LEDs exhibit an on-wafer integrated emission power of 77 mu W at 5 mA, which correlates to an external quantum efficiency (EQE) of 0.29% with 45 mu W emitted through the bottom sapphire substrate and 32 mu W emitted through the transparent top surface. After depositing a highly reflective aluminum reflector, a maximum emission power of 1.73 mW was achieved at 100 mA under pulsed mode operation with a maximum EQE of 0.35% as collected through the bottom substrate. (C) 2021 Chinese Laser Press