Suchergebnisse

We present a gas-phase process for surface patterning and 3D self-assembly of nanoparticles (NPs) of functional materials such as metals, oxides, and nitrides. The method relies on electrostatic assembly of free-flying NPs with unipolar charge produced in plasma sources. We demonstrate the capability of the process in self-assembly of NPs, with the size in the range 10-60 nm, into arrays of free-standing 3D microstructures with complex morphologies. Considering that the plasma nanoparticle sources are compatible with synthesis of a large library of material NPs, the process introduces a novel approach for 3D printing of various functional NPs, high-precision device integration of NPs on sub-micrometer scales, and large-area parallel surface patterning of NPs. ; Funding Agencies|Linkoping University; Knut and AliceWallenberg FoundationKnut & Alice Wallenberg Foundation [KAW 14.0276]; Swedish Government Strategic Research Area inMaterials Science on Functional Materials at Linkoping University [2009-00971]; AForsk Foundation [17-517]

Plasmonic response of free charges confined in nanostructures of plasmonic materials is a powerful means for manipulating the light-material interaction at the nanoscale and hence has influence on various relevant technologies. In particular, plasmonic materials responsive in the mid-infrared range are technologically important as the mid-infrared is home to the vibrational resonance of molecules and also thermal radiation of hot objects. However, the development of the field is practically challenged with the lack of low-loss materials supporting high quality plasmons in this range of the spectrum. Here, we demonstrate that degenerately doped InN nanocrystals (NCs) support tunable and low-loss plasmon resonance spanning the entire midwave infrared range. Modulating free-carrier concentration is achieved by engineering nitrogen-vacancy defects (InN1-x, 0.017 amp;lt; x amp;lt; 0.085) in highly degenerate NCs using a nonequilibrium gas-phase growth process. Despite the significant reduction in the carrier mobility relative to intrinsic InN, the mobility in degenerate InN NCs (amp;gt;60 cm(2)/(V s)) remains considerably higher than the carrier mobility reported for other materials NCs such as doped metal oxides, chalcogenides, and noble metals. These findings demonstrate feasibility of controlled tuning of infrared plasmon resonances in a low-loss material of III-V compounds and open a gateway to further studies of these materials nanostructures for infrared plasmonic applications. ; Funding Agencies|Knut and Alice Wallenberg Foundation [KAW 14.0276]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (faculty Grant SFO-Mat-LiU) [2009-00971]; EPSRC [EP/M024938/1]