One-dimensional 3C-SiC Nanostructures Optical/Electrical Properties Adjustment And Applications

Effective control of the optical/electrical properties of semiconductor materials is one of the important foundations of the device application.In this paper,the effective performance control of the cube silicon carbide(3C-SiC)is carried out by element doping and morphology adjustment.Then,the optical properties of 3C-SiC such as electronic structure and photoluminescence and electrical properties such as conductivity are studied.And their optical applications include photocatalysis and surface enhanced Raman scattering(SERS),electrical applications include electrochemical catalysis and photodetection are also conducted in-depth research.The influence of B,Al,N and P on the electronic structure and optical properties of 3C-SiC was investigated by using the first-principles calculations.The study shows that only B and N can satisfy the predictability of performance and meet the requirements of fine control.At the same time,the doping influence of the conductivity of 3C-SiC is studied.The result shows that only doping of B element can promote or reduce conductive ability of 3C-SiC.Therefore,the B element is selected to doping 3C-SiC to regulate its optical properties and electrical properties.For morphology control,3C-SiC single-crystal nanowires and B-doped 3C-SiC nanowires with a finned nanostructure were synthesized via the facile and simple carbothermal reduction of a mixture of low-cost gangue,carbon black and boric oxide powder.The obtained nanowires possess finned microstructure with fins about 100-200 nm in diameter and 10-20 nm in thickness.The diameter of the inner core stem is about 80 nm on average.And 3C-SiC nanobelts with different B-doping amounts are synthesized via catalyst-free pyrolysis of polymeric precursors of polysilazane,which have an average length of few hundreds ?m,a typical width of 4 ?m and thickness of about 120 nm.For photocatalysis application,due to the smaller band gap.the finned microstructure and the single crystalline nature,the B-doped 3C-SiC nanowires demonstrate efficient activity as high as 108.4 ?mol·h-1·g-1 for H2 production.which is about 20 times higher than that of 3C-SiC nanowhiskers and 2.6 times higher than the highest value reported in the literature for SiC materials.For SERS.it is found especially for B-doped 3C-SiC nanowires substrate,a detection of limit as low as 5×10-6 M is achieved and the EF reached up to 104.Such EF value is 10-fold of that of 3C-SiC nanowires and at least 2-fold higher than the previously reported values for most other semiconductor based SERS-active substrates.For photodetection application,the photodetectors based on individual single-crystalline 3C-SiC nanobelt with or without B-doped photodetectors were fabricated through photolithography,thermal evaporation,and lift-off process.The UV light photodetector based on B-doped SiC nanobelt with B of 0.31%mole percentage possess the maximum responsivity and EQE with 6.37 × 105 A·W-1 and 2.0 × 108%under 405 nm light at a power of 0.14 mW·cm-2,as well as a high stability.Besides,the detectivity as high as 6.86 × 1014 Jones is two order of magnitude more than the detectivity of a Si photodetector in the same spectral region(4 × 1012 Jones).Furthermore,benefiting from the excellent physical and chemical properties of SiC nanobelts,the UV and blue photodetectors can work at temperature as high as 300 ?,which holds great potential in optoelectronic circuits for harsh conditions.These high-performance,individual single-crystalline photodetectors demonstrate the unique possibilities of using SiC nanowires for the next-generation UV photodetectors in cost-effective commercial applications.