Post-doctoral position in Bordeaux : « Surface-Enhanced Raman Spectroscopy of laser-printed organic thin film transistors »
Supervisors: Vincent Rodriguez and Sébastien Bonhommeau.
Key words: micro-Raman spectrometry, surface-enhanced Raman spectroscopy, organic thin films.
Techniques: Raman spectrometry, UV-vis-IR absorption, Second Harmonic Generation charaterizations, Ellipsometry.
Required background: at least one of the following fields: IR and Raman spectroscopies, plasmonics, surface or tip-enhanced Raman spectroscopy.
For many applications within the microelectronics industry, the challenge is no longer the size reduction but the flexibly of materials and low production costs. In this context, a laser printing technique called LIFT (Laser-Induced Forward Transfer) has been developed in the frame of a preceding project. It allowed the printing of organic thin film transistors (OTFT) on various substrates. However, the performances of such OTFTs remained one to two orders of magnitude lower than their counterparts prepared by vacuum evaporation using masks to achieve the spatial resolution. A careful inspection of OTFTs is required hence in order to identify origins (quality of interfaces involved in the charges injection and transport notably,...) of these reduced performances and avoid them.
The successful applicant will participate to the shared effort to characterize monolayer and multilayer thin films produced by pulsed laser deposition and LIFT. In particular, the investigated OTFTs will be composed of 4 layers, namely the gate (G), an organic dielectric (OD) layer, an organic semiconducting (OSC) layer and the source/drain (SD) electrodes. The main challenge lies in the detailed study of the metal/organic interface. As the G and SD electrodes will be made of noble metals (either gold or silver), we propose to take advantage of the roughness of these noble metal layers to scrutinize G/OD and SD/OSC interfaces by means of surface-enhanced Raman spectroscopy (SERS). Other SERS platforms (such as films of nanoparticles, dot and nanorod arrays...) could be tested too. In addition, visible-IR micro-absorption measurements of these platforms could be realised to select the ideal irradiation wavelength for SERS, i.e. the wavelength allowing excitation in resonance with the localized surface plasmon band associated with the nanostructures. Confocal Raman spectroscopy, SHG(Second Harmonic Generation) techniques, spectroscopic ellipsometry and IR spectrometry might be used to obtain complementary chemical, structural and optical information about the layers and bulk materials. All the samples (reference monolayers, OTFTs and SERS platforms) will be prepared by our collaborators on the project.
The strongly motivated applicants must have a PhD degree in chemistry, physical-chemistry, physics or related disciplines. A solid knowledge in Raman spectrometry, plasmonics and/or SERS is required. Experimental skills in other linear and non-linear optical microscopies and in thin film characterization techniques will be highly appreciated but are not mandatory. To apply for this postdoctoral position, please send a CV, a motivation letter and the name of one referee to the following email address [log in to unmask], before Monday 22 July 2013. This postdoctoral position will be funded by the French research agency ANR (ILTO project – ANR Blanc 2011). It will be available from the 1st of September 2013 for a 1-year period (not renewable). The gross salary should be about 2400 euros/month corresponding to a net salary of about 2000 euros/month.
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