Yeon Sik Jung

Self-assembling materials are the building blocks of bottom-up nanofabrication processes, but they need to be templated to impose long-range order and eliminate defects. In this work, the self-assembly of a thin film of a spherical-morphology block copolymer is templated using an array of nanoscale topographical elements that act as surrogates for the minority domains of the block copolymer. The orientation and periodicity of the resulting array of spherical microdomains are governed by the comm

Templated self-assembly of a cylinder-forming poly(styrene-b-dimethylsiloxane) (PS-PDMS) diblock copolymer has been investigated for nanolithography applications. The large chi-parameter of the blocks and the use of a PDMS-brush substrate surface treatment are especially advantageous for achieving long-range ordering and minimizing defect densities, and the high Si content in PDMS leaves a robust oxide etch mask after two-step reactive ion etching. By adjusting mesa width and solvent-annealing v

Control over carrier type and doping levels in semiconductor materials is key for optoelectronic applications. In colloidal quantum dots (CQDs), these properties can be tuned by surface chemistry modification, but this has so far been accomplished at the expense of reduced surface passivation and compromised colloidal solubility; this has precluded the realization of advanced architectures such as CQD bulk homojunction solids. Here we introduce a cascade surface modification scheme that overcome

Self-assembly of a block copolymer into cylindrical and/or perforated lamellar arrays within substrate trenches can be extensively tuned during the solvent-annealing process. Following reactive-ion etching, SEM images reveal that the solvent mixing ratio and the vapor pressure determine the type of array obtained and influence the dimensions of the repeat unit. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not

The templated self-assembly of block copolymer (BCP) thin films can generate regular arrays of 10-50 nm scale features with good positional and orientational accuracy, but the ordering, registration and pattern transfer of sub-10-nm feature sizes is not well established. Here, we report solvent-annealing and templating methods that enable the formation of highly ordered grating patterns with a line width of 8 nm and period 17 nm from a self-assembled poly(styrene-b-dimethylsiloxane) (PS-PDMS) di

3D stacking of plasmonic nanostructures is achieved using a solvent-assisted nanotransfer printing (S-nTP) technique to provide extremely dense and regular hot spot arrays for highly sensitive surface-enhanced Raman spectroscopy (SERS) analysis. Moreover, hybrid plasmonic nanostructures obtained by printing the nanowires on a continuous metal film or graphene surface show significantly intensified SERS signals due to vertical plasmonic coupling.

Nanostructured conjugated organic thin films are essential building blocks for highly integrated organic devices. We demonstrate the large-area fabrication of an array of well-ordered 15 nm wide conducting polymer nanowires by using an etch mask consisting of self-assembled patterns of cylinder-forming poly(styrene-b-dimethylsiloxane) diblock copolymer confined in topographic templates. The poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) nanowires operated as an ethanol vapor sensor, sug

Thin films of block copolymers are widely seen as enablers for nanoscale fabrication of semiconductor devices, membranes, and other structures, taking advantage of microphase separation to produce well-organized nanostructures with periods of a few nm and above. However, the inherently three-dimensional structure of block copolymer microdomains could enable them to make 3D devices and structures directly, which could lead to efficient fabrication of complex heterogeneous structures. This article

Abstract Flexible energy‐storage devices have attracted growing attention with the fast development of bendable electronic systems. However, it still remains a challenge to find reliable electrode materials with both high mechanical flexibility/toughness and excellent electron and lithium‐ion conductivity. This paper reports the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible l

The formation of well-controlled circular patterns on the nanoscale is important for the fabrication of a range of devices such as sensors, memories, lasers, transistors, and quantum devices. Concentric, smooth ring patterns with tunable dimensions have been formed from a cylinder-forming poly(styrene- b-dimethylsiloxane) (PS-PDMS) diblock copolymer under confinement in shallow circular trenches. The high etch selectivity between PS and PDMS facilitates pattern transfer, illustrated by the fabri

Surface-enhanced Raman spectroscopy (SERS)-based protein analysis is a promising alternative to existing early stage diagnoses. However, SERS research conducted thus far accompanies challenges such as nonuniformity of plasmonic nanostructures, irregular coating of analytes, and denaturation of proteins, which seriously limit the practicability of suggested approaches. Here, we introduce a carboxylic acid-functionalized and graphitic nanolayer-coated three-dimensional SERS substrate (CGSS) fabric