Preparation Of Boron-doped Diamond Films And Their Applications In Electrochemistry

Boron doped diamond film has very broad application prospects in the field of electrochemistry.It shows the advantages of high sensitivity,fast response and strong anti-jamming etc.In the electrochemical sensor.In this paper,the preparation of boron doped diamond film,the electrochemical performance test and its performance in sensor of diamond electrode is studied.Boron doped diamond film was grown on the p-type silicon single crystal by hot filament chemical vapor deposition(HFCVD)technique.The effects of boron flow rate on the growth mechanism,quality and residual stress of diamond films were studied.The relationship between the flow rate of carbon source and the surface morphology,growth rate and grain size of boron-doped diamond films was analyzed.The electrochemical window size of boron-doped diamond electrodes in acid-alkali salt solution and the influence of PH on oxygen and hydrogen evolution over potential were analyzed.It was found that the electrode has good stability,precision and recovery in electrochemical sensing detection through the analysis.The influence of boron flow rate on the microstructure and residual stress of diamond films was studied.Trimethyl borate was selected as boron source to control doping accurately.The films were characterized by SEM,Raman spectroscopy and XRD.The results show that the film resistance decreases rapidly with the addition of boron until the resistance changes gently.When the gas flow rate ratio is hydrogen:(hydrogen + acetone)= 160:60,the growth of diamond grains is enhanced gradually when the boron flow rate is between 0 and 25 m L/min,while the growth of diamond grains is weakened when the boron flow rate reaches 35 ml/min,and the surface defects of diamond grains are increased.With the increase of boron flow rate,the number ratio of(111)and(110)crystal planes increased first.The film exhibits compressive stress,and the residual stress decreases first and then increases with the increase of boron flow rate.When the gas flow ratio is hydrogen:(hydrogen + trimethyl borate)= 160:20,the film growth rate increases with the increase of acetone flow rate,and the film compactness and grain size increase first and then decrease.The films deposited at the flow rate ratio of hydrogen:(hydrogen + acetone):(hydrogen + acetone)=160:60:20 only serve as diamond electrodes and exhibit good electrochemical performance in acid-alkali-salt solution.,and the electrochemical window in neutral solution can reach more than 3.2 V.The boron-doped diamond film electrode was fabricated as a sensor electrode for electrochemical determination in catechol solution,which showed irreversible oxidation reaction.At the scanning rate of 10 m V/s,the concentration of catechol showed a linear correlation with the peak current of oxidation peak.The detection range was 200.0?2000.0 mg/L,and it performed well in the measurement of precision,stability and recovery.