1. GaN/AlGaN Nanocolumn Ultraviolet Light-Emitting Diode Using Double-Layer Graphene as Substrate and Transparent Electrode
- Author
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Bjørn-Ove Fimland, Katsumi Kishino, Lyubomir Ahtapodov, Andreas Liudi Mulyo, Ida Marie Høiaas, Dong Chul Kim, Helge Weman, and Per Erik Vullum
- Subjects
Materials science ,Bioengineering ,02 engineering and technology ,Substrate (electronics) ,medicine.disease_cause ,law.invention ,law ,semiconductor nanocolumn ,medicine ,Ultraviolet light ,UV optoelectronics ,General Materials Science ,Sheet resistance ,Diode ,electrical injection ,business.industry ,Graphene ,Mechanical Engineering ,LED ,graphene ,General Chemistry ,nitride-based devices ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrode ,Optoelectronics ,0210 nano-technology ,business ,Ultraviolet ,Molecular beam epitaxy - Abstract
The many outstanding properties of graphene have impressed and intrigued scientists for the last few decades. Its transparency to light of all wavelengths combined with a low sheet resistance makes it a promising electrode material for novel optoelectronics. So far, no one has utilized graphene as both the substrate and transparent electrode of a functional optoelectronic device. Here, we demonstrate the use of double-layer graphene as a growth substrate and transparent conductive electrode for an ultraviolet light-emitting diode in a flip-chip configuration, where GaN/AlGaN nanocolumns are grown as the light-emitting structure using plasma-assisted molecular beam epitaxy. Although the sheet resistance is increased after nanocolumn growth compared with pristine double-layer graphene, our experiments show that the double-layer graphene functions adequately as an electrode. The GaN/AlGaN nanocolumns are found to exhibit a high crystal quality with no observable defects or stacking faults. Room-temperature electroluminescence measurements show a GaN related near bandgap emission peak at 365 nm and no defect-related yellow emission.
- Published
- 2019