Laser Absorption Scanning Tunneling Microscopy of Carbon Nanotubes

Abstract

We report single molecule laser absorption by carbon nanotubes stamped under ultrahigh vacuum onto Si(100)2x1:H surfaces. Absorption is detected by scanning tunneling microscopy. Images are obtained with and without modulated laser excitation using lock-in amplification and a rear-illumination geometry to reduce thermal effects. Noise appears at topographic edges and is analyzed by a quantitative model in terms of scan speed, mechanical instabilities, and feedback current fluctuations at the edge of the nanotubes. Noise due to mechanical instabilities is shown to persist even in the limit of slow scan speed.

Nanoscale properties of lead halide perovskites by scanning tunneling microscopy

“…To shine light onto the underlying mechanisms occurring when several external stressors are used simultaneously, STM studies including advanced light‐coupling techniques are desirable. Here, STM techniques such as single‐molecule absorption by STM (SMA‐STM) or novel photocurrent measurement protocols using STM have been developed which have been already applied successfully to other semiconductor systems 34,35,69‐71 . The SMA‐STM technique makes use of a unique light coupling geometry which avoids excessive heating of the tip‐sample junction thus allows precise investigation of the changes in the DOS under illumination.…”

Lateral Manipulation of Single‐Walled Carbon Nanotubes on H‐Passivated Si(100) Surfaces with an Ultrahigh‐Vacuum Scanning Tunneling Microscope

“…We hypothesize that NT1 was pivoted, rather than translated, across the surface, due to attractive interactions with NT2 and NT3 at the junction. The dramatic reduction in noise along the edge of NT1 can likely be attributed to improved alignment between the SWNT axis and the fast‐scan (horizontal) direction of the STM image 18. Moreover, the atomic‐scale cleanliness of the proximal H‐passivated Si(100) surface was not disrupted by the manipulation.…”

Nanoscale Mapping of Photo‐Induced Charge Carriers Generated at Interfaces of a Donor/Acceptor 2D‐Assembly by Light‐Assisted‐Scanning Tunneling Microscopy

“…[ 14 ] The group of W. Ho has shown that the absorption of a photon by a molecule involves a tunnel transport mechanism through its excited levels. [ 15 ] LA‐STM has also been extended to the characterization of light absorption by individual inorganic nanostructures such as carbon nanotubes [ 16 ] and quantum dots. [ 17 ]…”

“…[14] The group of W. Ho has shown that the absorption of a photon by a molecule involves a tunnel transport mechanism through its excited levels. [15] LA-STM has also been extended to the characterization of light absorption by individual inorganic nanostructures such as carbon nanotubes [16] and quantum dots. [17] In this framework, we have developed a LA-STM setup that aims at mapping the photocurrent resulting from charge transfer at the local scale between a monolayer of a donor polymer: the poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′] dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno [3,4-b]thiophene-4,6-diyl), called PTB7, and an acceptor species: the [6,6]-phenyl-C 71 -butyric acid methyl ester, called PC 71 BM, both successively deposited on the Au(111) surface.…”