退火对B掺杂纳米金刚石薄膜微结构和电化学性能的影响

采用热丝化学气相沉积法制备B掺杂纳米金刚石薄膜,并对薄膜进行真空退火处理,系统研究了不同退火温度对B掺杂纳米金刚石薄膜的微结构和电化学性能的影响.结果表明,当退火温度升高到800 ℃后,薄膜的Raman谱图中由未退火时在1157,1346,1470,1555 cm^-1处的4个峰转变为只有D峰和G峰,说明晶界上的氢大量解吸附量减少,并且D峰和G峰的积分强度比I_D/I_G值变为最小,即sp²相团簇

Influence of annealing on the microstructure and electrochemical properties of B-doped nanocrystalline diamond films

The annealing under different temperatures was performed on boron-doped nanocrystalline diamond films synthesized by hot filament chemical vapor deposition (HFCVD). The effects of annealing on the microstructure and electrochemical properties of films were systematically investigated. The results show that there are four peaks at 1157,1346,1470 and 1555 cm^-1 in Raman spectra of the unannealed sample. When the films were annealed at temperatures above 800 ℃, there are only two peaks of D and G band, indicating that the hydrogen in grain boundaries significantly decreased. The area-integrated intensity ratio of D band to G band (I_D/I_G) reaches minimum value, revealing that the cluster number or cluster size of sp² phase was reduced. The G peak position shifts to lower wave number, indicating an decrease in the ordering of graphitic component. The electrode exhibits the widest potential window and the highest oxygen evolution potential, and the quasi-reversible reaction occurs on the surface of the samples. The D peak is quite sharp and its intensity increases when the sample was annealed at 1000 ℃. The I_D/I_G value attains to the maximum value and the G peak position clearly shifts to higher value. The electrode exhibits the narrowest potential window and the lowest oxygen evolution potential, and the reversible electrochemical reaction occurs in the surface of the sample. The above results reveal that the cluster number or cluster size of sp² phase, the amounts of trans-polyacetylene related to hydrogen in the grain boundaries, the disordering of graphitic components and the boron diffusion in the nanocrystalline diamond films give contributions to the complex change in electrochemical properties of the films with the annealing temperature increasing.