Enhanced performance of GaN-based LEDs via electroplating of a patterned copper layer on the backside
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InGaN/GaN multi-quantum well light-emitting diodes (LEDs) are conventionally grown on a sapphire substrate due to a lack of compatible substrates with a high compressive strain. This is a result of the relatively large lattice, and thermal expansion coefficient mismatches between GaN and sapphire. The compressive strain is considered to be a major obstacle to further improve next-generation high-performance GaN-based LEDs. In this paper, we have designed, electroplated, and tested an efficient substrate using a patterned copper (Cu) layer on the backside of sapphire to relax the compressive strain in a GaN epilayer. The patterned Cu layer has a significant function in that it supports the GaN/sapphire LEDs with an external tensile stress. The external tensile stress is capable of compensating for the compressive strain in the GaN/sapphire LEDs by controlling the curvature of the wafer bowing. This patterned Cu layer, when applied to the GaN/sapphire LEDs, suppresses the compressive strain by up to 0.28 GPa. The GaN-based LEDs on this innovative and effective sapphire/Cu substrate offer improved optical and electrical performance.
This study was financially supported by Chonnam National University (Grant Number 2016-2443).
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Conflict of interest
The authors declare that they have no conflict of interest.
- 6.Chichibu SF, Uedono A, Onuma T, Haskell BA, Chakraborty A, Koyama T, Fini PT, Keller S, Denbaars SP, Speck JS, Mishra UK, Nakamura S, Yamaguchi S, Kamiyama S, Amano H, Akasaki I, Han J, Sota T (2006) Origin of defect-insensitive emission probability in In-containing (Al, In, Ga)N alloy semiconductors. Nat Mater 5:810–816CrossRefGoogle Scholar
- 7.Cao XA, Yang Y, Guo H (2008) On the origin of efficiency roll-off in InGaN-based light-emitting diodes. J Appl Phys 104:093108-4Google Scholar
- 34.Ryou J-H, Lee W, Limb J, Yoo D, Liu JP, Dupuis RD, Wu ZH, Fischer AM, Ponce FA (2008) Control of quantum-confined Stark effect in InGaN/GaNInGaN/GaN multiple quantum well active region by pp-type layer for III-nitride-based visible light emitting diodes. Appl Phys Lett 92:101113-3CrossRefGoogle Scholar