Catalyst-Free Vertical ZnO-Nanotube Array Grown on p-GaN for UV-Light-Emitting Devices
AuthorsAlwadai, Norah M.
Ajia, Idris A.
Flemban, Tahani H.
Ooi, Boon S.
Roqan, Iman S.
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Semiconductor and Material Spectroscopy (SMS) Laboratory
Embargo End Date2020-07-25
Permanent link to this recordhttp://hdl.handle.net/10754/656471
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AbstractOne-dimensional (1D) structures-based UV-light-emitting diode (LED) has immense potential for next-generation applications. However, several issues related to such devices must be resolved first, such as expensive material and growth methods, complicated fabrication process, efficiency droop, and unavoidable metal contamination due to metal catalyst that reduces device efficiency. To overcome these obstacles, we have developed a novel growth method for obtaining a high-quality hexagonal, well-defined, and vertical 1D Gd-doped n-ZnO nanotube (NT) array deposited on p-GaN films and other substrates by pulsed laser deposition. By adopting this approach, the desired high optical and structural quality is achieved without utilizing metal catalyst. Transmission electron microscopy measurements confirm that gadolinium dopants in the target form a transparent in situ interface layer to assist in vertical NT formation. Microphotoluminescence (PL) measurements of the NTs reveal an intense ZnO band edge emission without a defect band, indicating high quality. Carrier dynamic analysis via time-resolved PL confirms that the emission of n-ZnO NTs/p-GaN LED structure is dominated significantly by the radiative recombination process without efficiency droop when high carrier density is injected optically. We developed an electrically pumped UV Gd-doped ZnO NTs/GaN LED as a proof of concept, demonstrating its high internal quantum efficiency (>65%). The demonstrated performance of this cost-effective UV LED suggests its potential application in large-scale device production.
CitationAlwadai, N., Ajia, I. A., Janjua, B., Flemban, T. H., Mitra, S., Wehbe, N., … Roqan, I. S. (2019). Catalyst-Free Vertical ZnO-Nanotube Array Grown on p-GaN for UV-Light-Emitting Devices. ACS Applied Materials & Interfaces. doi:10.1021/acsami.9b06195
SponsorsI.S.R. and all members of the research team involved in this project acknowledge the financial support from General Directorate of Research Grants (405-34-AT), from King Abdul-Aziz City of Science and Technology (KACST), Kingdom of Saudi Arabia.
PublisherAmerican Chemical Society (ACS)