Metalorganic chemical vapor deposition-grown tunnel junctions for low forward voltage InGaN light-emitting diodes: epitaxy optimization and light extraction simulation
- 28 January 2021
- journal article
- research article
- Published by IOP Publishing in Semiconductor Science and Technology
- Vol. 36 (3), 035019
- https://doi.org/10.1088/1361-6641/abe0f7
Abstract
In this work, we demonstrate the detailed optimization of metalorganic chemical vapor deposition (MOCVD)-grown tunnel junctions (TJs) utilizing selective area growth (SAG) for regular size (0.1 mm2) and micro-size InGaN light-emitting diodes (LEDs and µLEDs). Finite-difference time-domain simulations show that the SAG apertures result in a more directional light emission of far-field radiation pattern for the SAG TJ LEDs grown on patterned sapphire substrate. Moreover, it is noted that the n-InGaN insertion layer and Si-doped concentration in the n+GaN TJs layer is essential to realize a low forward voltage (V f) in TJs LEDs. For both 0.1 mm2 LEDs and µLEDs, the V f is independent on the SAG aperture space varied from 3 to 8 µm when the Si-doping level in the n+GaN layer is as high as 1.7 × 1020 cm−3. The optimized TJ LEDs exhibit a comparable differential resistance of 1.0 × 10−2 Ω cm2 at 100 A cm−2 and a very small voltage penalty of 0.2–0.3 V compared to the conventional indium tin oxide contact LEDs. The low V f penalty is caused by a higher turn on voltage, which is the smallest one among the MOCVD-grown TJs LEDs and comparable to the best molecular beam epitaxy-grown TJs LEDs.Keywords
Funding Information
- Solid State Lighting and Energy Electronics Center, University of California Santa Barbara
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