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Dynamics of infrared excitations in boron doped diamond
摘要： We report on the investigation of relaxation dynamics of optical excitations in IIb high pressure high temperature (HPHT) diamond doped by natural boron and isotopically enriched 11boron. The measurements were performed with a pump-probe technique using short pump pulses from a wavelength-tunable infrared free electron laser. Lifetimes of excited boron states ranging from a few picoseconds to a few hundred picoseconds, have been derived from the obtained data. The relaxation rates depend on the pumped states, the pump intensity and the diamond lattice temperature. We discuss possible contributions to the optical and nonradiative intracenter relaxation rates observed in these experiments. Theoretical simulations support ultrafast relaxation by multiple phonon emission, for the electronic states with the energy gap exceeding the energy of optical phonon.
关键词： time-resolved spectroscopy,boron-doped diamond,diamond
更新于2025-11-14 15:14:40
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Molecular Functionalization of Planar Nanocrystalline and Porous Nanostructured Diamond to Form an Interface with Newborn and Adult Neurons
摘要： This article examines the ability of newly developed nanostructured porous boron-doped diamond (BDD) to form an interface with neural cells and the role of molecular functionalization by a polymer on this interface. Due to its high stability, biocompatibility, and electrical properties, BDD is a promising material for construction of neuroelectrodes. Nanostructuring and an increase in the surface specific area can further improve the sensitivity and performance of such electrodes. Here, porous BDD prepared in a multistep diamond deposition on a porous template consisting of a polymer and electrospun SiO2 fibers is examined. This work shows that this new material is biocompatible and does not exhibit any cytotoxicity on fibroblast cell lines. Further, this work shows that porous BDD supports regeneration of newborn and adult neurons when functionalized with poly-L-lysine.
关键词： nanocrystalline diamond,boron-doped diamond,enhanced surface area,neural interface,chemical functionalization
更新于2025-09-23 15:23:52
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Finite bias evolution of bosonic insulating phase and zero bias conductance in boron-doped diamond: A charge-Kondo effect
摘要： We report novel transport features in heavily boron-doped nanocrystalline diamond films, in particular an anomalous resistance peak near to the superconducting transition temperature and a strong zero bias conductance peak in the differential current-voltage spectra. The shape of the resistance-temperature curves near the critical temperature is seen to be strongly influenced by both magnetic field and bias current. As the bias current is lowered, the resistance peak becomes more pronounced, whereas when the magnetic field is varied the peak shifts towards lower temperatures. The resistance upturn shows a quadratic temperature dependence as expected for a Kondo transition. We find that a number of transport features such as resistance peak height, zero bias conduction peak height and width scale according to a power law dependence. We interpret these features as a result of a charge-Kondo effect where hole dopants act as degenerate Kondo impurities by opening additional pseudo-spin scattering channels.
关键词： bosonic insulating phase,zero bias conductance peak,charge-Kondo effect,boron-doped diamond,superconductivity
更新于2025-09-23 15:23:52
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Influence of pore size of Ti substrate on structural and capacitive properties of Ti/boron doped diamond electrode
摘要： This work is aimed at understanding the influence of pore size of titanium (Ti) substrate on the capacitive properties of boron doped diamond (BDD) electrode. BDD films were deposited on Ti substrates with five different pore sizes - 2.5, 5.0, 20.0, 30.0, 50.0 mm - using hot filament chemical vapor deposition (HFCVD). The pore size of substrate was found to cause significant variations in surface structure and capacitive properties of the Ti/BDD electrodes. The optimum pore size that resulted in best surface structure and capacitive properties was found to be 30.0 mm. The Ti30.0/BDD electrode was found to possess higher sp2-C bonds content, sp3-C bond with doped boron atom, more closely interlaced grains and bigger specific surface area than other electrodes. The maximum capacitance obtained for Ti30.0/BDD electrode was 53.3 mF cm-2, with minimum impedance value Rct of 4.8 U. The minimum capacitance of 1.07 mF cm-2 was obtained for the Ti50/BDD electrode, and the maximum impedance value Rct of 290 U was obtained by the Ti20.0/BDD electrode. Furthermore, the Ti30/BDD electrode possessed a favorable electrochemical stability of capacitance retention of 89.3% after 2070 cycles. A mechanism by which pore size affects the capacitance properties of the Ti/BDD electrode is proposed and discussed in this paper.
关键词： Capacitive property,Porous titanium substrate,Boron doped diamond,Surface structure
更新于2025-09-23 15:21:01
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Tunable self‐powered n‐SrTiO <sub/>3</sub> photodetectors based on varying CuS‐ZnS nanocomposite film (p‐CuZnS, p‐CuS, and n‐ZnS)
摘要： Dense Boron-doped diamond (BDD) composites were fabricated by high pressure and high-temperature sintering (HPHT) at 5 GPa and 1450 °C for 300 s in presence of Al, B and C as sintering additives. Phase compositions, microstructures, and electrochemical performances of sintered specimens were investigated by X-ray di?raction (XRD), scanning electron microscopy (SEM), and electrochemistry. Results suggested that Al3BC3 and Al4C were formed by in-situ reaction between sintering additives and diamond, which can promote densi?cation of BDD. In addition, BDD composites containing 10 wt% sintering additives exhibited the highest electrical resistivity (4.40 × 10?4 Ω m) and hole concentration (4.55 × 1025/m3). The working potential windows of BDD composite electrodes in 0.1 M H2SO4, 0.1 M Na2SO4 and 0.1 M NaOH electrolytes were estimated to 1.9 V, 2.9 V and 2.3 V, respectively. Electron transfer coe?cients of composite electrodes approached 0.5, con?rming good reversibility. Finally, methylene blue was completely degraded by BDD composite electrodes within 120 min using NaCl as supporting electrolyte.
关键词： High-pressure and high-temperature sintering,Boron-doped diamond,Electrochemical performances
更新于2025-09-11 14:15:04
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Morphology and Structure Properties of Boron-doped Diamond Films Prepared by Hot Cathode Direct Current Plasma Chemical Vapor Deposition
摘要： Boron-doped diamond (BDD) films were deposited by hot cathode direct current plasma chemical vapor deposition (HCDC-PCVD) according to various mixture ratios of CH4/H2/B(OCH3)3 gas. The Raman performances and surface morphologies of the BDD films were then characterized by Raman spectroscopy and scanning electron microscopy (SEM). Results indicated that the flow rate of B(OCH3)3 had marked effects on the growth characteristics of the produced boron-doped diamond films. The presence and concentration of the doped boron atoms significantly altered both the surface morphologies and structures of the diamond films. With increasing flow rate of B(OCH3)3, the crystal grain surfaces became smooth as visible under SEM. The B-doping levels in these films increased from 1.75 × 1019 cm-3 to a maximum of 2.4 × 1021 cm-3, estimated from the Raman spectra.
关键词： structural properties,boron-doped diamond (BDD) films,hot cathode direct current PCVD (HCDC-PCVD)
更新于2025-09-09 09:28:46