The diffusion behavior of vanadium (V) implanted in SiC is investigated by secondary ion mass spectrometry.Significant redistribution,especially out-diffusion of vanadium towards the sample surface, is not observed after 1650℃ annealing.Higher carrier concentration is obtained due to a lack of compensation of vanadium in the surface region.The electrical characteristics of Ni contacts to V-implanted n-type 4H-SiC are investigated using a linear transmission line method.A specific contact resistance as low as 4.4e-3Ω·cm2 is achieved after annealing at 1050℃ for 10min in gas ambient consisting of 90% N2 and 10% H2.X-ray diffraction analysis shows the formation of Ni2Si and graphite phase at the interface after annealing.This provides the evidence that the carbon vacancies,resulting from the out-diffusion of carbon atoms from SiC,contribute to the formation of ohmic contact through the reduction of effective Schottky barrier height for the transport of electrons.
Nature Communications 6: Article number: 7872 (2015); Published 5 August 2015; Updated 29 November 2017 This Article contains an error in which the scanning electron microscope image shown in Fig. 2b was included incorrectly. The original Fig. 2b showed yolk-shell microstructures, as previously published in Li, S.
Hydrogen sulfide (H2S) is the third endogenous gas in mammals that plays an important role in understanding human physiological and pathological processes. However, it remains difficult to measure H2S in living biological specimens due to interference of other biothiols (GSH, Cys, Hcy, and thiol-containing proteins) as well as low concentrations of H2S (as low as sub-nM). Here, we present Au@AgI core–shell plasmonic nanoparticles (PNPs) as highly sensitive probes to acquire sulfide rapid monitoring in biological environments. When the Au@AgI PNPs are exposed to sulfide, the AgI transforms into Ag2S, leading a change of local surface plasmon resonance (LSPR), thereby resulting in a color and light intensity change at the single nanoparticle level which can be monitored by dark-field microscopy (DFM). This strategy has an ultralow limit of detection (LOD) of 33 pM and great anti-interference ability for sulfide detection in biological environments. This method was successfully used for highly sensitive sulfide mapping in live cells and to record the changes of H2S levels in different brain regions of rats during acute cerebral ischemia, validating that this method suitable for trace sulfide sensing in biological environments. We anticipate that this sulfide sensor has potential applications for studying complex neurochemical changes.
The combination of novel materials and electrochemistry technologies can effectively detect a variety of biochemicals to facilitate understanding and monitoring of biological processes. In this study, an uncomplicated and environmentally friendly microemulsion method was developed to synthesize Co based nanocomposites (Co based NCs) containing Co3(PO4)2, Co(PO3)2, Co2(OH)PO4 and carbon structure as a nanostructured biomimetic enzyme for the detection of cellular O2•– release. Interestingly, Co based nanocomposites can act as nanoscale biological enzymes and catalyze superoxide anion (O2•–) oxidation at 0.2 V, which was significantly lower than the currently reported potential at 0.484 V. The designed O2•– sensor showed a wide linearity range from 3 nM to 0.15 μM and detection limit as low as 1.0 nM (S/N = 3). Its excellent selectivity and sensitivity toward O2•– sensing ability allow the Co based NCs modified sensor to electrochemically monitor O2•– release from human umbilical-vein endothelial cells (HUVECs). This result provides a reliable platform for fabricating biomimetic enzymes sensors with high sensitivity and durability in biological analysis and paves more routes for the detection of chemical signaling molecules from cells, in vivo or other biological systems.
In this work, series‐connected double‐junction tandem solar cells were fabricated by employing the complementary absorbing donors of tetraphenyldibenzoperiflanthene (DBP) and chloroaluminum phthalocyanine (ClAlPc). The tandem cell shows a high open circuit voltage of 1.57 V, summing those of single cells. The optical simulation and experimental results both demonstrate that the subcell (SC) sequence plays an important role in photocurrent and fill factor for tandem cells. It is helpful for current matching to use ClAlPc as a donor in the bottom SC for the ClAlPc‐DBP system, because the power conversion efficiency ( η PCE ) is increased by 7% in the ClAlPc‐DBP normal tandem cell relative to the DBP‐ClAlPc reverse tandem cell. The simulated external quantum efficiency (EQE) spectra of the SCs in the DBP‐ClAlPc reverse cell overlap with each other thus resulting in a current mismatch. Via optical modeling, an optimized ClAlPc‐DBP normal tandem cell exhibits a η PCE of 3.24% by slightly tuning layer thickness.
Estrogen receptor α (ERα) plays a pivotal role in the proliferation, differentiation, and migration of breast cancer (BC) cells, and aromatase (ARO) is a crucial enzyme in estrogen synthesis. Hence, it is necessary to inhibit estrogen production or the activity of ERα for the treatment of estrogen receptor-positive (ER
The miniaturization, integration, and increased power of electronic devices have exacerbated serious heat dissipation issues. Thermally conductive adhesives, which effectively transfer heat and firmly bond components, are critical for addressing these challenges. This paper innovatively proposed a composite comprising inorganic phosphate/alumina as a matrix and diamond as filler. The composite achieved an isotropic thermal conductivity (TC) of up to 18.96 W m
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
