作者：
Park, WounjhangDepartment of Electrical
Computer and Energy Engineering Materials Science and Engineering Program University of Colorado BoulderCO80309-0425 United States
We report the latest progress on plasmonic nanostructures for organic photovoltaic devices. Specifically, three aspects will be discussed: plasmon-exciton interaction, combined optical and electrical modeling and plas...
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Rapid progress in graphene-based applications is calling for new processing techniques for creating graphene components with different shapes,sizes,and edge *** we report a controlled cutting process for graphene shee...
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Rapid progress in graphene-based applications is calling for new processing techniques for creating graphene components with different shapes,sizes,and edge *** we report a controlled cutting process for graphene sheets,using nickel nanoparticles as a knife that cuts with nanoscale *** cutting proceeds via catalytic hydrogenation of the graphene lattice,and can generate graphene pieces with specifi c zigzag or armchair *** size of the nanoparticle dictates the edge structure that is produced during the *** cutting occurs along straight lines and along symmetry lines,defined by angles of 60ºor 120º,and is defl ected at free edges or defects,allowing practical control of graphene nano-engineering.
In optoelectronics, achieving electrical reconfigurability is crucial as it enables the encoding, decoding, manipulating, and processing of information carried by light. In recent years, two-dimensional van der Waals ...
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The mechanism of the crystal to amorphous transformation during ion damage in silicon has been investigated using high resolution lattice imaging electron microscopy. Sharp interfaces were observed between amorphous a...
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The mechanism of the crystal to amorphous transformation during ion damage in silicon has been investigated using high resolution lattice imaging electron microscopy. Sharp interfaces were observed between amorphous and crystalline regions in partially amorphous silicon. The critical displacement damage necessary to produce an amorphous layer for 11 MeV As implants was shown to increase with temperature and to agree well with the calculated displacement energy absorption versus depth.
Developing on-chip functional devices requires reliable fabrication methods with high resolution for miniaturization,desired components for enhanced performance,and high throughput for fast prototyping and mass ***,la...
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Developing on-chip functional devices requires reliable fabrication methods with high resolution for miniaturization,desired components for enhanced performance,and high throughput for fast prototyping and mass ***,laser-based bubble-pen lithography(BPL)has been developed to enable sub-micron linewidths,in situ synthesis of custom materials,and on-demand patterning for various functional components and *** exploits Marangoni convection induced by a laser-controlled microbubble to attract,accumulate,and immobilize particles,ions,and molecules onto different *** years have witnessed tremendous progress in theory,engineering,and application of BPL,which motivated us to write this ***,an overview of experimental demonstrations and theoretical understandings of BPL is ***,we discuss the advantages of BPL and its diverse applications in quantum dot displays,biological and chemical sensing,clinical diagnosis,nanoalloy synthesis,and *** conclude this review with our perspective on the challenges and future directions of BPL.
Bacterial discrimination is crucial for accurate microbiological diagnosis and timely antibiotic treatment. Surface-enhanced Raman spectroscopy (SERS) is an ideal technique due to its non-invasive, label-free molecula...
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Bacterial discrimination is crucial for accurate microbiological diagnosis and timely antibiotic treatment. Surface-enhanced Raman spectroscopy (SERS) is an ideal technique due to its non-invasive, label-free molecular sensing capabilities. By analyzing bacterial supernatants, containing various purine derivatives, SERS can differentiate bacterial species based on their unique spectral distributions. However, the same bacterial species with different antibiotic resistance may secrete similar purine derivatives, differing only slightly in composition. Furthermore, each purine derivative may have a different molecular affinity to the SERS substrate, making it difficult to distinguish the exact molecular ratio. To improve SERS-based bacterial discrimination, we propose an air-liquid microfluidics-integrated SERS system (ALM-SERS) that selectively adsorbs and detects bacterial secretions. By taking features of precise microdroplet manipulation and contact area from microfluidics and features of selective molecular adsorption and fingerprints characterization from the SERS technique, we successfully perform a "sequential molecular adsorption" strategy to address the signal interference of complicated molecular mixtures in existing SERS methods. As a proof of concept, we first evaluate the molecular affinity of purine derivatives and then demonstrate the competitive analyte adsorption using adenine/cytosine and hypoxanthine/uracil sample mixtures. Finally, we tested six bacterial supernatants, including two Gram types and four strains with identical taxonomy but differing antibiotic resistance. Another six clinically isolated bacterial samples with different antibiotic resistance were also applied. Our results showed that a successful bacterial discrimination between similar species was not possible using a single SERS spectrum. In summary, the ALM-SERS system offers a powerful approach for bacterial discrimination, even when spectral differences are subtle. Beyond microb
Transformation optics has formulated a versatile framework to mold the flow of light and tailor its spatial characteristics at *** its huge success in bringing scientific fiction(such as invisibility cloaking)into rea...
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Transformation optics has formulated a versatile framework to mold the flow of light and tailor its spatial characteristics at *** its huge success in bringing scientific fiction(such as invisibility cloaking)into reality,the coordinate transformation often yields extreme material parameters unfeasible even with ***,we demonstrate a new transformation paradigm based upon the invariance of the eigenspectra of the Hamiltonian of a physical system,enabled by *** creating a gradient-index metamaterial to control the local index variation in a family of isospectral optical potentials,we demonstrate broadband continuous supersymmetric transformation in optics,on a silicon chip,to simultaneously transform the transverse spatial characteristics of multiple optical states for arbitrary steering and switching of light *** a novel synergy of symmetry physics and metamaterials,our work provides an adaptable strategy to conveniently tame the flow of light with full exploitation of its spatial degree of freedom.
Understanding the thermodynamic properties of electrolyte solutions is of vital importance for a myriad of physiological and technological *** mean activity coefficientγ±is associated with the deviation of an el...
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Understanding the thermodynamic properties of electrolyte solutions is of vital importance for a myriad of physiological and technological *** mean activity coefficientγ±is associated with the deviation of an electrolyte solution from its ideal behavior and may be obtained by combining the Debye-Hückel(DH)and Born(B)***,the DH and B equations depend on the concentration and temperature-dependent static permittivity of the solutionεr(c,T)and the size of the solvated ions ri,whose experimental data is often not ***,we use a combination of molecular dynamics and density functional theory to predictεr(c,T)and ri,which enables us to apply the DH and B equations to any technologically relevant aqueous and nonaqueous electrolyte at any concentration and temperature of interest.
This paper demonstrates electrical detection of single strand deoxyribonucleic acid (ssDNA) conjugation by AlGaN/GaN hetero-structure field effect transistor (HFET) biological sensors. The probe ssDNA molecules are mo...
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This paper demonstrates electrical detection of single strand deoxyribonucleic acid (ssDNA) conjugation by AlGaN/GaN hetero-structure field effect transistor (HFET) biological sensors. The probe ssDNA molecules are modified by thiol groups. The immobilization of probe molecules is achieved by S-Au bonding on a thin layer of gold film in the sensing area. The immobilization and hybridization process are firstly implemented on Si surfaces and checked by fluorescent and atomic force microscopy (AFM) imaging. The hybridization process is monitored on AlGaN/GaN HFETs. Time-dependent current change is observed when a matched ssDNA solution is applied, while no response is observed for a mismatched ssDNA sequence. The DNA hybridization process is dominated by the conjugation between matched ssDNA sequences in the first few tens of seconds. After that, the hybridization process is dominated by mass transfer processes and saturation of the immobilized probe ssDNA molecules.
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