My research

See also: my publication list, or the FEBIP homepage.

In short: My PhD research topic concerns improving the properties of nano-structures created by the technique of electron-beam-induced deposition (EBID).

Electron-beam-induced deposition (EBID), also sometimes referred to as electron-beam-induced processing (EBIP) or electron-beam assisted deposition (EBAD) [1,2] is a promising technique for nano-scale rapid prototyping and nano-lithography alternative [3,4]. It is a direct-write process capable of creating conductive or insulating three-dimensional nano-structures within a few minutes inside a scanning electron microscope (SEM); the deposited material depends on the precursor chosen. It can be likened to a local CVD process, with the decomposition of the gaseous precursor caused by the interaction of an electron beam with a solid substrate. The energy transferred from the electron beam to the adsorbed precursor gas molecules in the vicinity of the beam irradiation point dissociates the precursor into a volatile and non-volatile part. The non-volatile part collects at the substrate and forms local material growth. Typical applications of EBID include nanowire deposition [5], contacting carbon nanotubes [6], and growing tips for field emission [7] and atomic and magnetic force microscopy [8].

Another common application of EBID is to write conductive lines at a position chosen by the SEM operator, for example to create contact electrodes to nano-devices. This is done by depositing platinum metal from methylcyclopentadienyl platinum trimethyl. This precursor, being organometallic, results in carbon-rich material being deposited rather than pure platinum, and the resistivity of the resulting nanostructure is usually around 10^8 µΩ.cm. The low purity and conductivity is often detrimental to the target application. It is therefore relevant to reduce the structure's resistivity as far as possible, ideally to the level of bulk platinum (10.62 µΩ.cm).

[1] Randolph SJ, Fowlkes JD and Rack PD 2006 Crit. Rev. Solid State and Mat. Sci. 31 55-89
[2] Silvis-Cividjian N, Hagen CW and Kruit P 2005 J. Appl. Phys. 98 084905
[3] van Dorp WF, van Someren B, Hagen CW, Kruit P and Crozier PA 2005 Nano Letters 5 1303--7
[4] Botman A, Mulders JJL, Weemaes R and Mentink S 2006 Nanotechnology 17 3779--85
[5] Molhave K, Madsen DN, Dohn S and Boggild P 2004 Nanotechnology 15, 1047-1053
[6] Brintlinger T, Fuhrer MS, Melngailis J, Utke I, Bret T, Perentes A, Hoffmann P, Abourida M and Doppelt P 2005 J. Vac. Sci. Technol. B 23, 3174-3177
[7] Koops HWP, Schoessler C, Kaya A and Weber M 1996 J. Vac. Sci. Technol. B 14, 4105-4109
[8] Lau YM, Chee PC, Thong JTL and Ng V 2002 J. Vac. Sci. Technol. A 20, 1295-1302