High-efficiency green micro-LEDs with GaN tunnel junctions grown hybrid by PA-MBE and MOCVD

We fabricated p-i-n tunnel junction (TJ) contacts for hole injection on c-plane green micro-light-emitting diodes (micro-LEDs) by a hybrid growth approach using plasma-assisted molecular beam epitaxy (PA-MBE) and metal organic chemical vapor deposition (MOCVD). The TJ was formed by an MBE-grown ultra-thin unintentionally doped InGaN polarization layer and an n(++)/n(+)-GaN layer on the activated p(++)-GaN layer prepared by MOCVD. This hybrid growth approach allowed for the realization of a steep doping interface and ultrathin depletion width for efficient inter-band tunneling. Compared to standard micro-LEDs, the TJ micro-LEDs showed a reduced device resistance, enhanced electroluminescence intensity, and a reduced efficiency droop. The size-independent J-V characteristics indicate that TJ could serve as an excellent current spreading layer. All these results demonstrated that hybrid TJ contacts contributed to the realization of high-performance micro-LEDs with long emission wavelengths. (C) 2021 Chinese Laser Press

Automated summary

Hybrid p-i-n tunnel junction (TJ) contacts were fabricated for hole injection on c-plane green micro-light-emitting diodes (micro-LEDs) using a combination of plasma-assisted molecular beam epitaxy (PA-MBE) and metal organic chemical vapor deposition (MOCVD). The TJ structure allowed for a steep doping interface and ultrathin depletion width, leading to reduced device resistance, enhanced electroluminescence intensity, and decreased efficiency droop in comparison to standard micro-LEDs. The size-independent J-V characteristics suggested that TJ could serve as an excellent current spreading layer.