Over 1000 channel nitride-based micro-light-emitting diode arrays with tunnel junctions

Abstract

We fabricated nitride-based micro-LED arrays with a small number of fabrication process steps by using a combination of tunnel junctions and patterned n-GaN cathode lines. A use of the combination enables us to skip a couple of process steps required in standard LED array fabrication. A 10 × 10 channel matrix-addressable LED array with a 10 × 16 µm2 emission regions and a 25 µm pitch lengths showed uniform operating voltages and light output intensities, indicating good yield due to the small number of process steps used. In addition, microdisplay of over 1000 (14 × 72) channels was successfully demonstrated. The new array structure with the tunnel junction and n-GaN cathode line provides a high density and a high yield simultaneously.

Micro-light-emitting diodes with III–nitride tunnel junction contacts grown by metalorganic chemical vapor deposition

“…The voltage of TJ LEDs has been further improved by adding a p-InGaN contact layer. [21][22][23][24] TJ LEDs have also been grown by MBE 25,26) or a hybrid MOCVD-MBE approach where LEDs are grown by MOCVD and TJ contacts by MBE. [27][28][29] Because of their small areas, µLEDs with TJ contacts grown solely by MOCVD may overcome the issues of passivated p-GaN through lateral activation.…”

GaInN-based tunnel junctions with graded layers

“…T he first GaInN-based tunnel junction for current injection from n-layers to p-layers was demonstrated in 2001. 1) Because the tunnel junctions made of other III-V semiconductors have been adopted in various devices, [2][3][4] such a GaInN-based tunnel junction is also expected to be utilized to improve device performance in not just tandem solar cells 5) and cascaded LEDs, [6][7][8][9][10][11][12] but also in micro-LEDs, 13,14) their arrays, 15) lasers, 16,17) and vertical cavity surface emitting lasers (VCSELs). 6,18) At that time, however, the voltage drop at the GaInN tunnel junction was high, about 0.6 V at 50 A=cm 2 , and further reduction in tunnel junction resistance was demanded.…”

Monolithic integration of tricolor micro-LEDs and color mixing investigation by analog and digital dimming

“…These findings were explained in terms of QCSE screening inherent to nitride LEDs driven at high current density. Upgrading such a tricolor device following the recent progress made on tunnel junction μLEDs [34][35][36] and InGaN/AlGaN-based red LEDs 7) could enable the fabrication of full nitride RGB microdisplays.…”