Preparation Of Large-diameter Semiconducting Single-walled Carbon Nanotubes And Research On Carbon Nanotube-Based Photodetectors

Owing to their unique one dimensional tubular structure,single-walled carbon nanotubes(SWCNTs)demonstrate many excellent properties.Their broad-spectrum response and high light absorption coefficient make it a promising photodetection material.However,carbon nanotube based high performance electronic devices have not yet been practically applied.The main reason is that the problem of macro preparation of SWCNTs with uniform structure and single conductive properties has not been solved.Floating catalyst chemical vapor deposition(FCCVD)is expected to achieve low-cost,continuous,and macroscopic growth of SWCNTs.In this study,enrichment of SWCNTs with specific transport properties was studied systematically based on the FCCVD technique.And the application of SWCNTs in photodetector was also investigated.The main results obtained are as follows:Synthesis of high-quality,large-diameter semiconducting single-walled carbon nanotubes(s-SWCNT).Because low-carbon alcohol molecular can generate hydroxyl radicals at high temperatures,and there is chemical reactivity difference between metallic SWCNTs(m-SWCNTs)and s-SWCNTs,m-SWCNTs can be selectively removed by hydroxyl radicals etching,and high quality s-SWCNTs were successfully prepared.The results showed that the OH/C ratio is the key to the growth of semiconductor-enriched SWCNTs.The obtained high quality s-SWCNTs exhibited a high oxidation resistance temperature of?670? in air due to their good structural integrity,and the diameter distribution is in 1.8 nm-2.3 nm.The flexible,large-area SWCNTs based bolometric photodetectors was constructed using the large-diameter SWCNTs.The photodetector,with a wide response range from 500 nm to 1900 nm of light,demonstrated a high performance with an responsivity of up to 65.37 mA/W with a bias voltage of 0.2 V in air,which is better than that of many other photodetectors based on SWCNTs.Moreover,the effect of film transmittance,film width,and the structure of SWCNTs(diameter,purity,semiconducting SWCNTs content,etc.)on device performance was studied.All these excellent properties illustrate that these high quality large-diameter SWCNTs that can be potentially used in high performance photodetectors.