Journal ArticleDOI
Surface-Effect-Induced Optical Bandgap Shrinkage in GaN Nanotubes
Youngsin Park,Geunsik Lee,Mark J. Holmes,Christopher C. S. Chan,Benjamin P. L. Reid,Jack A. Alexander-Webber,Robin J. Nicholas,Robert A. Taylor,Kwang S. Kim,Sang W. Han,Woochul Yang,Yongcheol Jo,Jongmin Kim,Hyunsik Im +13 more
TLDR
It is found that the conduction band edge is mainly dominated by surface atoms, and that a larger number of surface atoms for the tube is likely to increase the bandwidth, thus reducing the optical bandgap.Abstract:
We investigate nontrivial surface effects on the optical properties of self-assembled crystalline GaN nanotubes grown on Si substrates. The excitonic emission is observed to redshift by ∼100 meV with respect to that of bulk GaN. We find that the conduction band edge is mainly dominated by surface atoms, and that a larger number of surface atoms for the tube is likely to increase the bandwidth, thus reducing the optical bandgap. The experimental findings can have important impacts in the understanding of the role of surfaces in nanostructured semiconductors with an enhanced surface/volume ratio.read more
Citations
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High-Power Lithium Batteries from Functionalized Carbon Nanotube Electrodes
TL;DR: Layer-by-layer techniques are used to assemble an electrode that consists of additive-free, densely packed and functionalized multiwalled carbon nanotubes, which had a gravimetric energy approximately 5 times higher than conventional electrochemical capacitors and power delivery approximately 10 timesHigher than conventional lithium-ion batteries.
Journal ArticleDOI
A Highly Responsive Self-Driven UV Photodetector Using GaN Nanoflowers
Neha Aggarwal,Shibin Krishna,Alka Sharma,Lalit Goswami,Dinesh Kumar,Sudhir Husale,Govind Gupta +6 more
TL;DR: In this paper, a self-driven, highly sensitive, fast responding GaN nanoflower based UV photodetector is reported, which exhibits very low dark current (approximate to nA) with a very high responsivity (132 mA W-1) and detectivity (2.4 x 10(10) Jones).
Journal ArticleDOI
Dopant-stimulated growth of GaN nanotube-like nanostructures on Si(111) by molecular beam epitaxy
Alexey D. Bolshakov,Alexey D. Bolshakov,Alexey M. Mozharov,G. A. Sapunov,Igor Shtrom,Igor Shtrom,N. V. Sibirev,N. V. Sibirev,Vladimir V. Fedorov,Vladimir V. Fedorov,Evgeniy Ubyivovk,Maria Tchernycheva,G. E. Cirlin,G. E. Cirlin,G. E. Cirlin,Ivan Mukhin,Ivan Mukhin +16 more
TL;DR: A theoretical model of the novel nanostructure formation which includes the role of the dopant Si is proposed which shows that the highest value of donor concentration in the nanostructures exceeds 5∙1019 cm−3.
Journal ArticleDOI
Morphologically tailored CuO photocathode using aqueous solution technique for enhanced visible light driven water splitting
Ajay Kushwaha,Ajay Kushwaha,Roozbeh Siavash Moakhar,Roozbeh Siavash Moakhar,Gregory K. L. Goh,Goutam Kumar Dalapati +5 more
TL;DR: In this article, aqueous solution approach was used to grow CuO nanostructures on a fluorine doped tin oxide (FTO) coated glass substrate, and X-ray diffraction pattern and Xray photoelectron spectroscopy revealed formation of pure CuO crystalline phase.
References
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Journal ArticleDOI
Single-crystal gallium nitride nanotubes.
Joshua E. Goldberger,Rongrui He,Yanfeng Zhang,Sangkwon Lee,Haoquan Yan,Heon Jin Choi,Peidong Yang,Peidong Yang +7 more
TL;DR: An ‘epitaxial casting’ approach for the synthesis of single-crystal GaN nanotubes with inner diameters of 30–200 nm and wall thicknesses of 5–50nm is reported, applicable to many other semiconductor systems.
Journal ArticleDOI
Nanotechnology. Thin solid films roll up into nanotubes.
Oliver G. Schmidt,Karl Eberl +1 more
TL;DR: It is shown here that nanotubes can be formed from thin solid films of almost any material at almost any position, once these films are released from their substrate.
High-Power Lithium Batteries from Functionalized Carbon Nanotube Electrodes
TL;DR: Layer-by-layer techniques are used to assemble an electrode that consists of additive-free, densely packed and functionalized multiwalled carbon nanotubes, which had a gravimetric energy approximately 5 times higher than conventional electrochemical capacitors and power delivery approximately 10 timesHigher than conventional lithium-ion batteries.
Journal ArticleDOI
High-power lithium batteries from functionalized carbon-nanotube electrodes
Seung Woo Lee,Naoaki Yabuuchi,Betar M. Gallant,Shuo Chen,Byeong Su Kim,Paula T. Hammond,Yang Shao-Horn +6 more
TL;DR: In this article, layer-by-layer techniques are used to assemble an electrode that consists of additive-free, densely packed and functionalized multi-walled carbon nanotubes, which can store lithium up to a reversible gravimetric capacity of approximately 200 mA h g(-1) while also delivering 100 kW kg(electrode) of power and providing lifetimes in excess of thousands of cycles.
Journal ArticleDOI
Spintronics and pseudospintronics in graphene and topological insulators.
Dmytro Pesin,Allan H. MacDonald +1 more
TL;DR: The status of efforts to achieve long spin-relaxation times in graphene with its weak spin- orbit coupling, and to achieve large current-induced spin polarizations in topological-insulator surface states that have strong spin-orbit coupling are reviewed.
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