Nanowire and electronic device
The nanowire ( 10 ) comprises a first region ( 1 ), a second region ( 2 ), and a third region ( 3 ), wherein the diameter (c) of the second region ( 2 ) is greater than the diameters (a) of the first and the third region ( 1, 3 ), therewith interrupting at least partially the quantization of the nanowire ( 10 ) and giving the second region a smaller bandgap. The second region ( 2 ) has a length (b) in axial direction of less than 100 nm, preferably less than 20 nm. The nanowire ( 10 ) can be used in an (opto-)electronic device having electrodes as a quantum dot, a single-electron transistor, or the like.
1 . A nanowire with a first, a second, and a third region in an axial arrangement,
wherein the second region adjoins the first and the third regions and has a length of less than 100 nm in axial direction, and
wherein the second region has a greater diameter than the first and the third region, in which first and third regions quantization effects take place.
2 . A nanowire as claimed in claim 1 , characterized in that the second region has a length in axial direction of less than 20 nm.
3 . A nanowire as claimed in claim 1 , characterized in that the first and the third region have an average diameter in radial direction of at most 10 nm.
4 . A nanowire as claimed in claim 3 , characterized in that the second region has a maximum diameter of 50 nm.
5 . A nanowire as claimed in claim 1 , characterized in that the first region is n-type doped and the second region is p-type doped.
6 . A nanowire as claimed in claim 1 , characterized in that a fourth and a fifth region are present, which fourth region is enclosed in axial direction by the third and the fifth region and in axial direction has a length of less than 100 nm, and which fourth region is structurally different from the third and fifth regions in that it has a smaller bandgap.
7 . An electronic device provided with a first and a second electrode which are interconnected by means of at least one nanowire, characterized in that the nanowire as claimed in claim 1 is present.
8 . An electronic device as claimed in claim 7 , characterized in that the nanowire of claim 6 is present, and in that a first and a second gate electrode are present, wherein a perpendicular protection of the first gate electrode on the nanowire overlaps the second region and a perpendicular projection of the second gate electrode on the nanowire overlaps the fourth region.
9 . A method of manufacturing nanowires as claimed in claim 1 , by means of catalytic growth, wherein the second region is grown at a higher temperature than the first and the third region.
10 . A method as claimed in claim 9 , characterized in that the method comprises the steps of:
growing the first regions of the nanowires at a first growing temperature;
growing the second regions of the nanowires at a second growing temperature which is higher than the first growing temperature; and
growing the third regions of the nanowires at a third growing temperature which is lower than the second growing temperature.
11 . A method of manufacturing nanowires as claimed in claim 1 , comprising the steps of:
providing a patterned etching mask at a surface of a semiconductor substrate; and
etching the semiconductor substrate so as to form the nanowires in a direction substantially perpendicular to the surface, during which the etching rate is reduced while the second region of greater diameter is being formed.
12 . A method as claimed in claim 11 , wherein the nanowires are removed from the semiconductor substrate.
13 . A dispersion of nanowires as claimed in claim 1 , in a dispersing agent.