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The high-performance determination of heavy metal ions (Cd2+) in water sources is significant for the protection of public health and safety. We have developed a novel sensor of nanograss boron and nitrogen co-doped diamond (NGBND) to detect Cd2+ using a simple method without any masks or reactive ion etching. The NGBND electrode is constructed based on the co-doped diamond growth mode and the removal of the non-diamond carbon (NDC) from the NGBND/NDC composite. Both the enlarged surface area and enhanced electrochemical performance of the NGBND film are achievable. Scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse anodic stripping voltammetry (DPASV) were used to characterize the NGBND electrodes. Furthermore, we used a finite element numerical method to research the current density near the tip of NGBND. The NGBND sensor exhibits significant advantages for detecting trace Cd2+ via DPASV. A broad linear range of 1 to 100 μg L−1 with a low detection limit of 0.28 μg L−1 was achieved. The successful application of this Cd2+ sensor indicates considerable promise for the sensitive detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

Nano-needle boron-doped diamond (NNBDD) films increase their performance when used as electrodes in the determination of Pb2+. We develop a simple and economical route to produce NNBDD based on the investigation of the diamond growth mode and the ratio of diamond to non-diamond carbon without involving any templates. An enhancement in surface area is achievable for NNBDD film. The NNBDD electrodes are characterized through scanning electron microscopy, Raman spectroscopy, X-ray diffraction, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse anodic stripping voltammetry (DPASV). Furthermore, we use a finite-element numerical method to research the prospects of tip-enhanced electric fields for sensitive detection at low Pb2+ concentrations. The NNBDD exhibits significant advantages and great electrical conductivity and is applied to detect trace Pb2+ through DPASV. Under pre-deposition accumulation conditions, a wide linear range from 1 to 80 µgL−1 is achieved. A superior detection limit of 0.32 µgL−1 is achieved for Pb2+, which indicates great potential for the sensitive detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

Different defective structures of nitrogen-doped 6H-SiC single crystals were examined using a combination of laser scanning confocal microscopy (LSCM), scanning electron microscope (SEM) and KOH-KCO etching. The form, depth and size of the defects in etched silicon carbide (SiC) crystals were observed by LSCM. Using these 3D LSCM images, defective structures varying in the growth direction were observed from a side view for the first time. To study the size, depth and form of defect etch pits in detail, we observed the defect etch pits configuration in some volumes through taking 3D LSCM pictures. Information on defects obtained using this approach will be very helpful for investigation of MP and SD formation mechanism in conducting SiC substrates, as well as the observation of polytype stability in nitrogen-doped SiC crystals. [ABSTRACT FROM AUTHOR]