The growth and ordering of C60 molecules on the WO2/W（110） surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy （STM and STS）, low-energy electron diffraction （LEED）, and ...The growth and ordering of C60 molecules on the WO2/W（110） surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy （STM and STS）, low-energy electron diffraction （LEED）, and density functional theory （DFT） calculations. The results indicate the growth of a well-ordered C60 layer on the WO2/W（110） surface in which the molecules form a close-packed hexagonal structure with a unit cell parameter equal to 0.95 nm. The nucleation of the C60 layer starts at the substrate＇s inner step edges. Low-temperature STM of C60 molecules performed at 78 K demonstrates well-resolved molecular orbitals within individual molecules. In the C60 monolayer on the WO2/W（110） surface, the molecules are aligned in one direction due to intermolecular interaction, as shown by the ordered molecular orbitals of individual C60. STS data obtained from the C60 monolayer on the WO2/W（110） surface are in good agreement with DFT calculations.展开更多
The structural stability of C60 films under the bombardment of 1.95 GeV Kr ions is investigated.The irradiated C60 films were analyzed by Fourier Transform Infrared(FTIR) spectroscopy and Raman scattering technique.Th...The structural stability of C60 films under the bombardment of 1.95 GeV Kr ions is investigated.The irradiated C60 films were analyzed by Fourier Transform Infrared(FTIR) spectroscopy and Raman scattering technique.The analytical results indicate that the irradiation induced a decrease of icosahedral symmetry of C60 molecule and damage of C60 films;different vibration modes of C60 molecule have different irradiation sensitivities;the mean efficient damage radius obtained from experimental data is about 1.47 nm,which is in good agreement with thermal spike model prediction.展开更多
在超高真空中采用分子束外延(molecular beam epitaxial)技术进行C60分子在硅(111)-7×7表面的生长,并利用扫描隧道显微镜进行原位研究.室温下,相对于无层错半胞(unfaulted half unit cell),C60更易于吸附在有层错半胞(faulted half...在超高真空中采用分子束外延(molecular beam epitaxial)技术进行C60分子在硅(111)-7×7表面的生长,并利用扫描隧道显微镜进行原位研究.室温下,相对于无层错半胞(unfaulted half unit cell),C60更易于吸附在有层错半胞(faulted half unit cell).表面台阶处的电子悬挂键密度最高,通过控制温度和时间进行退火处理后,C60分子会向着台阶的方向扩散并聚集.测量分子在不同吸附位置的直径和高度,发现由于不同位置分子与衬底的相互作用强度的不同,其分子直径和高度也存在一定差异.还研究了C60分子在Si(111)-7×7表面的多层生长模式,并且通过600℃退火处理在硅表面形成了有序的单层结构,从而实现了C60分子在硅表面从Stankski-Krastanov三维岛状模式到Frank-van der Merwe层状生长模式的转变.展开更多
By using nonequilibrium Green＇s function method and first-principles calculations, the electronic transport properties of doped C60 molecular devices were investigated. It is revealed that the C60 molecular devices s...By using nonequilibrium Green＇s function method and first-principles calculations, the electronic transport properties of doped C60 molecular devices were investigated. It is revealed that the C60 molecular devices show the metal behavior due to the interaction between the C60 molecule and the metal electrode. The current-voltage curve displays a linear behavior at low bias, and the currents have the relation of MI〉M3〉M4〉M2 when the bias voltage is lower than 0.6 V. Electronic transport properties are affected greatly by the doped atoms. Negative differential resistance is found in a certain bias range for C60 and C58BN molecular devices, but cannot be observed in C59B and C59N molecular devices. These unconventional effects can be used to design novel nanoelectronic devices.展开更多
文摘The growth and ordering of C60 molecules on the WO2/W（110） surface have been studied by low-temperature scanning tunnelling microscopy and spectroscopy （STM and STS）, low-energy electron diffraction （LEED）, and density functional theory （DFT） calculations. The results indicate the growth of a well-ordered C60 layer on the WO2/W（110） surface in which the molecules form a close-packed hexagonal structure with a unit cell parameter equal to 0.95 nm. The nucleation of the C60 layer starts at the substrate＇s inner step edges. Low-temperature STM of C60 molecules performed at 78 K demonstrates well-resolved molecular orbitals within individual molecules. In the C60 monolayer on the WO2/W（110） surface, the molecules are aligned in one direction due to intermolecular interaction, as shown by the ordered molecular orbitals of individual C60. STS data obtained from the C60 monolayer on the WO2/W（110） surface are in good agreement with DFT calculations.
基金supported by the National Natural Science Foundation of China (10835010,10675150,10175084)the National Basic Research Program of China (2010CB832902)
文摘The structural stability of C60 films under the bombardment of 1.95 GeV Kr ions is investigated.The irradiated C60 films were analyzed by Fourier Transform Infrared(FTIR) spectroscopy and Raman scattering technique.The analytical results indicate that the irradiation induced a decrease of icosahedral symmetry of C60 molecule and damage of C60 films;different vibration modes of C60 molecule have different irradiation sensitivities;the mean efficient damage radius obtained from experimental data is about 1.47 nm,which is in good agreement with thermal spike model prediction.
文摘在超高真空中采用分子束外延(molecular beam epitaxial)技术进行C60分子在硅(111)-7×7表面的生长,并利用扫描隧道显微镜进行原位研究.室温下,相对于无层错半胞(unfaulted half unit cell),C60更易于吸附在有层错半胞(faulted half unit cell).表面台阶处的电子悬挂键密度最高,通过控制温度和时间进行退火处理后,C60分子会向着台阶的方向扩散并聚集.测量分子在不同吸附位置的直径和高度,发现由于不同位置分子与衬底的相互作用强度的不同,其分子直径和高度也存在一定差异.还研究了C60分子在Si(111)-7×7表面的多层生长模式,并且通过600℃退火处理在硅表面形成了有序的单层结构,从而实现了C60分子在硅表面从Stankski-Krastanov三维岛状模式到Frank-van der Merwe层状生长模式的转变.
基金Project(07JJ3102) supported by the Natural Science Foundation of Hunan Province, ChinaProject(1343-74236000006) supported by the Graduate Foundation of Hunan Province, ChinaProject(11MY20) supported by the Mittal Entrepreneurship Program of China
文摘By using nonequilibrium Green＇s function method and first-principles calculations, the electronic transport properties of doped C60 molecular devices were investigated. It is revealed that the C60 molecular devices show the metal behavior due to the interaction between the C60 molecule and the metal electrode. The current-voltage curve displays a linear behavior at low bias, and the currents have the relation of MI〉M3〉M4〉M2 when the bias voltage is lower than 0.6 V. Electronic transport properties are affected greatly by the doped atoms. Negative differential resistance is found in a certain bias range for C60 and C58BN molecular devices, but cannot be observed in C59B and C59N molecular devices. These unconventional effects can be used to design novel nanoelectronic devices.
