钯金属吸附对半导体性碳纳米管电输运的影响

Effect of palladium adsorption on the electrical transport of semiconducting carbon nanotubes

利用物理蒸发技术,在半导体性的碳纳米管上沉积钯金属,利用导电原子力显微镜检测钯吸附对碳纳米管电输运的影响.结果表明:沉积的钯在碳纳米管上形成纳米颗粒,随着钯颗粒密度的增加,半导体性碳纳米管逐渐向金属性转变.利用第一性原理计算了吸附有钯原子的半导体性单壁碳纳米管的能带结构.研究发现,钯的覆盖率越高,其禁带宽度越窄,直至为零,定性说明了实验结果的合理性.

The metal Pd is deposited on semiconducting single-walled carbon nanotubes （SWNTs） by physical vapor deposition.The image of scanning electron microscopy shows that the Pd nanoparticles （10—30 nm） are formed on the carbon nanotubes.It is found by the conductive atomic force microscopy that with the increase of Pd nanoparticles,the semiconducting carbon nanotube is changed gradually into a metallic one.Furthermore,our density functional theory calculation demonstrates that with the Pd adsorption increasing the band gap of the SWNT becomes smaller,and eventually disappears,which is in good agreement with the experimental result.