Molecular scale electronics
![This animation of a rotating carbon nanotube shows its 3D structure.](/Images/godic/202501/27/Kohlenstoffnanoroehre_Animation1330.gif")
![Hydrogen can be removed from individual H2TPP molecules by applying excess voltage to the tip of a scanning tunneling microscope (STAM, a); this removal alters the current-voltage (I-V) curves of TPP molecules, measured using the same STM tip, from diode-like (red curve in b) to resistor-like (green curve). Image (c) shows a row of TPP, H2TPP and TPP molecules. While scanning image (d), excess voltage was applied to H2TPP at the black dot, which instantly removed hydrogen, as shown in the bottom part of (d) and in the re-scan image (e). Such manipulations can be used in single-molecule electronics.[6]](/Images/godic/202501/27/Dehydrogenation_of_H2TPP_by_STM1330.jpg")
![Graphical representation of a rotaxane, useful as a molecular switch.](/Images/godic/202501/27/Rotaxane_cartoon1330.jpg")
Molecular scale electronics, also called single-molecule electronics, is a branch of nanotechnology that uses single molecules, or nanoscale collections of single molecules, as electronic components. Because single molecules constitute the smallest stable structures imaginable this miniaturization is the ultimate goal for shrinking electrical circuits.