A5003990668- Nanowire Synthesis and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Molecular Junctions and Nanostructures
- Semiconductor materials and interfaces
- Semiconductor materials and devices
- CO2 Reduction Techniques and Catalysts
- Surface and Thin Film Phenomena
- Quantum and electron transport phenomena
- Plasmonic and Surface Plasmon Research
- Electrochemical Analysis and Applications
- Photonic Crystals and Applications
- Photonic and Optical Devices
- Ga2O3 and related materials
- Socioeconomic Development in MENA
- Conducting polymers and applications
- Ionic liquids properties and applications
- Force Microscopy Techniques and Applications
- Near-Field Optical Microscopy
University of North Carolina at Chapel Hill
2017-2025
Intense electromagnetic fields localized within resonant photonic nanostructures provide versatile opportunities for engineering nonlinear optical effects on a subwavelength scale. For dielectric structures, bound states in the continuum (BICs, nonradiative modes that exist radiation continuum) are an emerging strategy to localize and intensify fields. Here, we report efficient second third harmonic generation from Si nanowires (NWs) encoded with BIC quasi-BIC resonances. In situ dopant...
Semiconductor photoelectrodes are regularly coupled to solid-state heterogeneous catalysts perform solar-driven reduction of CO2. Less frequently, molecular employed better control the reactivity toward desired products, yet development robust semiconductor/molecule interfaces has proven challenging. Here, we demonstrate that a 2-3 nm thermal oxide layer on Si exhibits stability in aqueous solution, high photovoltage, and photocurrent density ∼10 mA/cm2 for photoelectrochemical homogeneous...
Ratcheting effects play an important role in systems ranging from mechanical socket wrenches to biological motor proteins. The underlying principle is convert a fluctuating, unbiased force into unidirectional motion. Here, we report the ratcheting of electrons at room temperature using semiconductor nanowire with precisely engineered asymmetry. Modulation diameter creates cylindrical sawtooth geometry broken inversion symmetry on nanometer-length scale. In two-terminal device, this structure...
In situ mid-infrared spectroscopy is a powerful technique for understanding the mechanism of CO2 reduction (CO2R) catalysts because it enables direct detection catalytic intermediates and products. Moreover, spectroelectrochemistry (SEC), coupling with electrochemistry, allows spectroscopic changes to be correlated applied potentials reveal potential-dependent that are often relevant photoelectrochemical reactions. Hybrid photoelectrodes, composed narrow bandgap semiconductor, like silicon...
Although silicon (Si) nanowires (NWs) grown by a vapor-liquid-solid (VLS) mechanism have been demonstrated for range of photonic, electronic, and solar-energy applications, continued progress with these NW-based technologies requires increasingly precise compositional morphological control the growth process. However, VLS typically encounters problems such as nonselective deposition on sidewalls, inadvertent kinking, unintentional or inhomogeneous doping, catalyst-induced gradients. Here, we...
Nanowires (NWs) with axial p-i-n junctions have been widely explored as microscopic diodes for optoelectronic and solar energy applications, their performance is strongly influenced by charge recombination at the surface. We delineate how photovoltaic of these dictated not only surface but also complex seemingly counterintuitive interplay diode geometry, that is, radius ( R) intrinsic length Li), velocity S). An analytical model to describe relationships developed compared finite-element...
The modern scientific world is exciting but poses numerous challenges in the form of juggling work–home life, structural barriers for underrepresented minorities, and information overload. Here we discuss ways to overcome these roadblocks promote growth individuals as scientists. [Graphical abstract image credit: Photoshop]
Abstract Electrical scanning probe microscopies (SPM) use ultrasharp metallic tips to obtain nanometer spatial resolution and are a key tool for characterizing nanoscale semiconducting materials systems. However, these not passive probes; their high work functions can induce local band bending whose effects depend sensitively on the geometry material properties thus inherently difficult quantify. We sequential finite element simulations first explore magnitude distribution of charge...
Aryl diazonium electrografting is a powerful method for imparting molecular functionality onto various substrates by forming stable carbon-surface covalent bond. While the high reactivity of aryl radical intermediate makes this fast and reliable, it can also lead to formation an insulating disordered multilayer film. These thick films affect electrochemical performance, especially semiconductor used in photoelectrochemical applications. We studied effects film thickness composition...
We have confirmed the presence of narrow, degenerately-doped axial silicon nanowire (SiNW) p-n junctions via off-axis electron holography (EH). SiNWs were grown vapor-solid-liquid (VLS) mechanism using gold (Au) as catalyst, silane (SiH4), diborane (B2H6) and phosphine (PH3) precursors, hydrochloric acid (HCl) to stabilize growth. Two types growth carried out, in each case we explored with both n/p p/n sequences. In first type, abruptly switched dopant precursors at desired junction...
We have confirmed the presence of narrow, degenerately-doped axial silicon nanowire (SiNW) $p$-$n$ junctions via off-axis electron holography (EH). SiNWs were grown vapor-solid-liquid (VLS) mechanism using gold (Au) as catalyst, silane (SiH$_{4}$), diborane (B$_{2}$H$_{6}$) and phosphine (PH$_{3}$) precursors, hydrochloric acid (HCl) to stabilize growth. Two types growth carried out, in each case we explored with both $n$/$p$ $p$/$n$ sequences. In first type, abruptly switched dopant...