Amorphous Carbon Monolayer: A van der Waals Interface for High-Performance Metal Oxide Semiconductor Devices.

Ultrasmall-scale semiconductor devices (≤5 nm) are advancing technologies, such as artificial intelligence and the Internet of Things. However, the further scaling of these devices poses critical challenges, such as interface properties and oxide quality, particularly at the high-/semiconductor interface in metal-oxide-semiconductor (MOS) devices. Existing interlayer (IL) methods, typically exceeding 1 nm thickness, are unsuitable for ultrasmall-scale devices.

Data on microstructural and optoelectronic properties of electrodeposited silver mesh transparent conducting electrodes.

Electrodeposited Ag mesh transparent conducting electrodes (TCEs) based on self-cracking templates can achieve high optical transmittances and low sheet resistances by controlling the shape of the self-cracking templates and electrodeposition duration. The surface coverage of the mesh is mainly determined by the surface shape of the self-cracking template. Electrodeposition of Ag can adjust the thickness of the mesh, significantly reducing the sheet resistance while maintaining the high optical transmittance of the TCEs.

Optimal CdS Buffer Thickness to Form High-Quality CdS/Cu(In,Ga)Se Junctions in Solar Cells without Plasma Damage and Shunt Paths.

CdS has been known to be one of the best junction partners for Cu(In,Ga)Se (CIGS) in CIGS solar cells. However, the use of thick CdS buffer decreases the short-circuit current density of CIGS solar cells. There are two obstacles that limit the use of ultrathin CdS.

Thermal stability data of silver nanowire transparent conducting electrode.

The authors have recently reported the enhanced thermal stability of silver nanowire (AgNW) network transparent electrodes by electrodeposition method [1]. AgNW networks are known to break into droplets at elevated temperatures (spherodization temperature) that are still much lower than the bulk Ag melting temperature. This phenomenon is known as Rayleigh instability.

Data on the effect of CdS on the lateral collection length of charge carriers for Cu(In,Ga)Se solar cells with mesh transparent conducting electrodes.

Mesh transparent conducting electrodes (TCEs) have been successfully employed to Cu(In,Ga)Se (CIGS) solar cells (Lee et al., 2018; Jang et al., 2017; Lee et al.

High resolution atomic force and Kelvin probe force microscopy image data of InAs(001) surface using frequency modulation method.

This article provides data on the scanning tunnelling microscopy (STM), atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) images of InAs(001) surface. Using the frequency-modulation (FM) method in AFM and KPFM, atomic resolution topography and contact potential difference (CPD) images of InAs(001) surface were obtained. The InAs(001) surface reconstruction images observed by STM and AFM are compared.

Effects of Density and Diameter on Surface Optical Phonon Modes in GaAs Nanowire Bundles.

We report the systematic investigation of the surface optical phonon modes in Au-catalyzed GaAs nanowires grown on an Au pre-patterned GaAs(111)B substrate using -Raman spectroscopy. We employed electron-beam dose rate as a control parameter during the substrate patterning step for adjusting the nanowire base diameter and coverage, which are independent from the nanowire growth conditions. We have experimentally studied the effect of the fill factor and average diameter on the surface optical phonon modes and explained the red-shift and broadening of the surface optical phonon frequencies by employing the dielectric continuum model.

Nondestructive Characterizations of Au-Catalyzed GaAs Nanowires on GaAs(111)B Substrates via Identifications of 1st Order Optical Phonon Modes Using -Raman Spectroscopy.

We report the relation between the catalyst patterning conditions and the intensity of the 1st order Raman active modes in Au-catalyzed GaAs nanowire bundles. We fabricated e-beam lithographically Au-patterned GaAs(111)B substrates by varying the patterning conditions (e-beam dose rate, dot-size and interdot-spacings), and grew GaAs nanowires via vapor-liquid-solid process using a solid-source molecular beam epitaxy. To understand the effects of the substrate preparation conditions and resulting morphologies on the optical characteristics of 1st order transverse optical and longitudinal optical phonon modes of GaAs, we characterized the nanowire bundles using complementary -Raman spectroscopy and scanning electron microscopy as a function of the e-beam dose rate (145-595 C/cm²), inter-dot spacing (100 and 150 nm) and pattern size (100 and 150 nm).

Electrodeposited Silver Nanowire Transparent Conducting Electrodes for Thin-Film Solar Cells.

Silver nanowire (AgNW) networks have demonstrated high optical and electrical properties, even better than those of indium tin oxide thin films, and are expected to be a next-generation transparent conducting electrode (TCE). Enhanced electrical and optical properties are achieved when the diameter of the AgNWs in the network is fairly small, that is, typically less than 30 nm. However, when AgNWs with such small diameters are used in the network, stability issues arise.

Raman Spectroscopic Characterizations of Self-Catalyzed InP/InAs/InP One-Dimensional Nanostructures on InP(111)B Substrate using a Simple Substrate-Tilting Method.

We report optical phonon vibration modes in ensembles of self-catalyzed InP/InAs/InP multi core-shell one-dimensional nanostructures (nanopillars and nanocones) grown on InP(111)B substrates using liquid indium droplets as a catalyst via metal-organic chemical vapor deposition. We characterized the Raman vibration modes of InAs E(TO), InAs A(TO), InAs E(LO), InP E(TO), InP A(LO), and InP E(LO) from the ensemble of as-grown nanostructures. We also identified second-order Raman vibration modes, associated with InP E(2TO), E(LO+TO), and E(2LO), in the InP/InAs/InP core-shell nanopillars and nanocones.

Data on lateral photocurrent along a Cu(In,Ga)Se thin film as a function of air exposure time.

Wavelength-dependent (i.e. penetration-depth-dependent) lateral photocurrent ( ) measurement has been used to extract depth-resolved profiles, where is the minority carrier collection length by diffusion.

Dataset on the generation of red-kinked current-voltage curves in Cu(In,Ga)Se solar cells due to buffer/window interfacial defects.

Red-kinked current-voltage characteristics in silver nanowire transparent electrode based Cu(In,Ga)Se solar cells have been reported [1-3]. The author has recently revealed that the buffer/window interfacial defects cause the generation of red-kinked current-voltage characteristics in the solar cells [1]. This article provides the dataset regarding the red-kink for Cu(In,Ga)Se solar cells as a function of the donor density in n-type window and CdS buffer/window interfacial defect density.

Data on lateral collection length of charge carriers depending on pre-white-light soaking process for metal mesh transparent electrode based Cu(In,Ga)Se solar cells.

The authors have recently reported silver nanowire based Cu(In,Ga)Se solar cells [1,2]. Metal mesh based transparent electrodes other than the silver nanowire can be also employed or have a potential to provide a better performance for the solar cells. To select a suitable electrode for a solar cell among metal meshes, it is required to have data on the lateral collection length of charge carriers in the targeted cell.

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in Cu(In,Ga)Se2 Thin-film Solar Cells.

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes normally result in very poor cell performance. Embedding or sandwiching silver nanowires using moderately conductive transparent materials, such as indium tin oxide or zinc oxide, can improve cell performance.

Micro-Raman Spectroscopy in Self-Catalyzed Indium Phosphide Nanostructures: Morphology and Substrate Effects.

We report the effect of morphology and substrate of self-catalyzed indium phosphide (InP) nanostructures on phonon vibration modes. Using liquid indium as a catalyst, we grew self-catalyzed InP nanocones and nanopillars on single crystal substrates of InP(111)B, Si(111), and Si(100) via metal-organic chemical vapor epitaxy. Due to crystal symmetry breaking in one-dimensional nanostructure, longitudinal-optical (LO) and transverse-optical (TO) phonon modes are clearly resolved with the strong anisotropic behavior.

Understanding of the formation of shallow level defects from the intrinsic defects of lead tri-halide perovskites.

Organic-inorganic hybrid perovskites have unique electronic properties in which deep level defects are rarely formed. This unique defect characteristic is the source of the long carrier diffusion length. This theoretical study shows what causes this characteristic formation of shallow level defects in lead tri-halide perovskites.

Suppressed Formation of Conductive Phases in One-Pot Electrodeposited CuInSe2 by Tuning Se Concentration in Aqueous Electrolyte.

The single-bath electrochemical deposition of CuInSe2 often leads to short-circuit behavior of the resulting solar cells due to the high shunt conductance. In this study, in an attempt to resolve this problem, the influence of the Se precursor concentration (CSe) on electrodeposited CuInSe2 films and solar cell devices is examined in the CSe range of 4.8 to 12.

Self-Catalyzed Growth and Characterization of In(As)P Nanowires on InP(111)B Using Metal-Organic Chemical Vapor Deposition.

We report the growth of vertical <111>-oriented InAs x P1-x (0.11 ≤ x ≤ 0.27) nanowires via metal-organic chemical vapor deposition in the presence of indium droplets as catalysts on InP(111)B substrates at 375 °C.

Systematic analysis of the unique band gap modulation of mixed halide perovskites.

Solar cells based on organic-inorganic hybrid metal halide perovskites have been proven to be one of the most promising candidates for the next generation thin film photovoltaic cells. Mixing Br or Cl into I-based perovskites has been frequently tried to enhance the cell efficiency and stability. One of the advantages of mixed halides is the modulation of band gap by controlling the composition of the incorporated halides.

Nanoscale Joule heating and electromigration enhanced ripening of silver nanowire contacts.

Solution-processed metallic nanowire thin film is a promising candidate to replace traditional indium tin oxide as the next-generation transparent and flexible electrode. To date however, the performance of these electrodes is limited by the high contact resistance between contacting nanowires; so improving the point contacts between these nanowires remains a major challenge. Existing methods for reducing the contact resistance require either a high processing power, long treatment time, or the addition of chemical reagents, which could lead to increased manufacturing cost and damage the underlying substrate or device.

Photoreaction of matrix-isolated dihydroazulene-functionalized molecules on Au{111}.

Dihydroazulenes are photochromic molecules that reversibly switch between two distinct geometric and conductivity states. Molecular design, surface attachment, and precise control over the assembly of such molecular machines are critical in order to understand molecular function and motion at the nanoscale. Here, we use surface-enhanced Raman spectroscopy on special atomically flat, plasmonically enhanced substrates to measure the photoreaction kinetics of isolated dihydroazulene-functionalized molecules assembled on Au{111}, which undergo a ring-opening reaction upon illumination with UV light and switch back to the initial isomer via thermal relaxation.

Novel solution processing of high-efficiency Earth-abundant Cu2 ZnSn(S,Se)4 solar cells.

A novel solution-based approach is presented to process earth-abundant Cu(2)ZnSn(S,Se)(4) absorbers using fully dissolved CZTS precursors in which each of the elemental constituents intermix on a molecular scale. This method enables the low-temperature processing of chemically clean kesterite films with excellent homogeneity. The high performance of resulting optoelectronic devices represents a chance to extend the impact of CZTS into the next chapter of thin-film solar cells.

Silver nanowire composite window layers for fully solution-deposited thin-film photovoltaic devices.

A silver nanowire-indium tin oxide nanoparticle composite and its successful application to fully solution processed CuInSe(2) solar cells as a window layer are demonstrated, effectively replacing the traditionally sputtered both intrinsic zinc oxide and indium tin oxide layers. The devices utilizing the nanocomposite window layer demonstrate photovoltaic parameters equal to or even beyond those with sputtered intrinsic zinc oxide and indium tin oxide contacts.

Visibly transparent polymer solar cells produced by solution processing.

Visibly transparent photovoltaic devices can open photovoltaic applications in many areas, such as building-integrated photovoltaics or integrated photovoltaic chargers for portable electronics. We demonstrate high-performance, visibly transparent polymer solar cells fabricated via solution processing. The photoactive layer of these visibly transparent polymer solar cells harvests solar energy from the near-infrared region while being less sensitive to visible photons.

Dispersal state of multiwalled carbon nanotubes elicits profibrogenic cellular responses that correlate with fibrogenesis biomarkers and fibrosis in the murine lung.

We developed a dispersal method for multiwalled carbon nanotubes (MWCNTs) that allows quantitative assessment of dispersion on profibrogenic responses in tissue culture cells and in mouse lung. We demonstrate that the dispersal of as-prepared (AP), purified (PD), and carboxylated (COOH) MWCNTs by bovine serum albumin (BSA) and dipalmitoylphosphatidylcholine (DPPC) influences TGF-β1, PDGF-AA, and IL-1β production in vitro and in vivo. These biomarkers were chosen based on their synergy in promoting fibrogenesis and cellular communication in the epithelial-mesenchymal cell trophic unit in the lung.