Size-independent low voltage of InGaN micro-light-emitting diodes with epitaxial tunnel junctions using selective area growth by metalorganic chemical vapor deposition

High performance InGaN micro-sin light-emitting diodes (mu LEDs) with epitaxial tunnel junctions (Ds) were successfully demonstrated using selective area growth (SAG) by metalorganic chemical vapor deposition (MOCVD). Patterned n + GaN/n-GaN layers with small holes were grown on top of standard InGaN blue LEDs to form Ds using SAG. TJ mu LEDs with squared mesa ranging from 10x10 to 100x1(X) mu m(2) were fabricated. The forward voltage (V-f) in the reference TJ mu LEDs without SAG is very high and decreases linearly from 4.6 to 3.7 V at 20 A/cm(2) with reduction in area from 10(XX) to 1(X) um(2), which is caused by the lateral out diffusion of hydrogen through sidewall. By contrast, the V-f at 20 A/cm(2) in the TJ mu LEDs utilizing SAG is significantly reduced to be 3.24 to 3.31 V. Moreover, the V-f in the SAG TJ mu LEDs is independent on sizes, suggesting that the hydrogen is effectively removed through the holes on top of the p-GaN surface by SAG. The output power of SAG TJ mu LEDs is similar to 10% higher than the common mu LEDs with indium tin oxide (ITO) contact. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement