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Full-Text Articles in Nanoscience and Nanotechnology

Metal-Assisted Etching Of Silicon Molds For Electroforming, Ralu Divan, Dan Rosenthal '14, Karim Ogando, Leonidas E. Ocola, Daniel Rosenmann, Nicolaie Moldovan Sep 2013

Metal-Assisted Etching Of Silicon Molds For Electroforming, Ralu Divan, Dan Rosenthal '14, Karim Ogando, Leonidas E. Ocola, Daniel Rosenmann, Nicolaie Moldovan

Student Publications & Research

Ordered arrays of high-aspect-ratio micro/nanostructures in semiconductors stirred a huge scientific interest due to their unique one-dimensional physical morphology and the associated electrical, mechanical, chemical, optoelectronic, and thermal properties. Metal-assisted chemical etching enables fabrication of such high aspect ratio Si nanostructures with controlled diameter, shape, length, and packing density, but suffers from structure deformation and shape inconsistency due to uncontrolled migration of noble metal structures during etching. Hereby the authors prove that a Ti adhesion layer helps in stabilizing gold structures, preventing their migration on the wafer surface while not impeding the etching. Based on this finding, the authors demonstrate …


Nanophase Stability In A Granular Ferh-Cu System, Radhika Barua, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis Aug 2013

Nanophase Stability In A Granular Ferh-Cu System, Radhika Barua, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis

Donald Heiman

A granular system of FeRh-based nanoprecipitates (∼10–15 nm diameter) embedded in a rapidly solidified copper ribbon matrix was found to transit from a metastable tetragonal L10 (AuCu-1-type) structure to a stable B2 (CsCl-type) structure upon annealing-induced coarsening to ∼94 nm. The hysteretic magnetic transition observed at ∼100 K develops a gradual broadening that accompanies the L10 → B2 crystal structure transition. It is proposed that the Cu matrix influences the structural and magnetic properties of the FeRh-based nanoparticles through interfacial strain and chemical effects. These results emphasize the sensitivity of the magnetostructural response of FeRh to changes in the nanostructural …


Nanophase Stability In A Granular Ferh-Cu System, Radhika Barua, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis Jul 2013

Nanophase Stability In A Granular Ferh-Cu System, Radhika Barua, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis

Felix Jiménez-Villacorta

A granular system of FeRh-based nanoprecipitates (∼10–15 nm diameter) embedded in a rapidly solidified copper ribbon matrix was found to transit from a metastable tetragonal L10 (AuCu-1-type) structure to a stable B2 (CsCl-type) structure upon annealing-induced coarsening to ∼94 nm. The hysteretic magnetic transition observed at ∼100 K develops a gradual broadening that accompanies the L10 → B2 crystal structure transition. It is proposed that the Cu matrix influences the structural and magnetic properties of the FeRh-based nanoparticles through interfacial strain and chemical effects. These results emphasize the sensitivity of the magnetostructural response of FeRh to changes in the nanostructural …


Electrochemical Nanofabrication Using Polyacrylamide Hydrogel As Soft Stamps, Wen Sun, Hai-Tao Fan, Da-Xiao Zhang, Dong-Jie Hu, Yong-Liang Zhou Jun 2013

Electrochemical Nanofabrication Using Polyacrylamide Hydrogel As Soft Stamps, Wen Sun, Hai-Tao Fan, Da-Xiao Zhang, Dong-Jie Hu, Yong-Liang Zhou

Journal of Electrochemistry

The fabrication resolution of electrochemical wet stamping (E-WETS) was enhanced to several hundred nanometers from several ten micrometers by using polycarylamide gel (PAG) as soft stamps and through optimized processes. The PAG stamp was cured on a nanopatterned soft mold and soaked with 0.2 mol·L-1 KCl solution, then contacted with a silicon wafer with gold film and applied with electric field. And the gold nanopatterns were achieved by the selective anodic dissolving, the diameter of fabricated gold spot was around 200 nm. The parameters which affected the fabrication processes have been discussed in detail.


Femtosecond Laser Patterned Templates And Imprinted Polymer Structures, Deepak Rajput May 2013

Femtosecond Laser Patterned Templates And Imprinted Polymer Structures, Deepak Rajput

Doctoral Dissertations

Femtosecond laser machining is a direct-write lithography technique by which user-defined patterns are efficiently and rapidly generated at the surface or within the bulk of transparent materials. When femtosecond laser machining is performed with tightly focused amplified pulses in single-pulse mode, transparent substrates like fused silica can be surface patterned with high aspect ratio (>10:1) and deep (>10 μm) nanoholes. The main objective behind this dissertation is to develop single-pulse amplified femtosecond laser machining into a novel technique for the production of fused silica templates with user-defined patterns made of high aspect ratio nanoholes. The size of the …