Role of V-defect density on the performance of III-nitride green LEDs on sapphire substrates
- Univ. of California, Santa Barbara, CA (United States). Materials Dept.
In this paper, we experimentally investigated the role of V-defect density on the performance of green III-nitride LEDs grown on sapphire substrates by metalorganic chemical vapor deposition. We systematically varied the threading dislocation (TD) density from 4 × 108 to 1 × 109 cm-2 by changing the V/III ratio during initial high temperature GaN growth. A 30-period InGaN/GaN superlattice promoted V-defect formation and growth at TDs, where the density of V-defects was correlated to the TD density. By interrupting the LED growth and examining the surface of the active region, we quantified the average size and density of V-defects. In a series of LEDs, we measured a systematic decrease in forward voltage (VF) with V-defect density. At a V-defect density of 5.0 × 108 cm-2 and TD density of 1 × 109 cm-2, green LED devices were demonstrated with λ = 523 nm and VF = 2.94 V at 20 A cm-2. These results highlight the potential of using V-defect engineering to achieve low VF long wavelength LEDs on sapphire substrates, where opening of remaining threading dislocations into V-defects presents an opportunity for further VF reduction.
- Research Organization:
- Univ. of California, Santa Barbara, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE); Solid State Lighting and Energy Electronic Center (SSLEEC)
- Grant/Contract Number:
- EE0008204; DMR 11-21053
- OSTI ID:
- 1848708
- Alternate ID(s):
- OSTI ID: 1775948
- Journal Information:
- Journal of Crystal Growth, Vol. 560-561, Issue C; ISSN 0022-0248
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Low dislocation GaN via defect-filtering, self-assembled SiO2-sphere layers.
Low-Dislocation-Density GaN from a Single Growth on a Textured Substrate