Cluster tool for local material growth (of nano to millimeter structures applying laser irradiation and reactive gas)

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The proposed instrument serves for the fabrication of nano to millimeter structures, i.e. for local material growth, whereby the processes partially run laser-assisted and/or in reactive gas atmosphere. Given its combined functionalities, the instrument can be named “cluster-tool of the next generation” and as such take a leading role for future technologies. Whereas in a classical cluster tool vacuum chambers with different sputter targets or evaporation sources are joined, the new system counts on the combination of inkjet printing with laser-assisted processes for additive and subtractive manufacturing. The laser-assisted processes comprise multiphoton polymerization for smallest structures as well as laser ablation and laser transformation additionally on a larger scale. A special feature is the possibility of laser processing in a reaction chamber, which allows the usage of reactive gases for material transformation and synthesis. This process can be conducted at slightly reduced pressure, whereas generally the cluster tool of the next generation runs at ambient atmosphere, allowing cost-effective fabrication. By combining the different processes, finally complete devices can be grown in a single system. In the course of this, structural and opto-electronic investigations using Raman and time-resolved photoluminescence measurements take place in between the different process steps, so to say in-line. Starting point for the application of the proposed instrument is the field of renewable energies, in particular photovoltaics, with the aim of maximizing energy conversion with a minimum amount of material usage. With respect to efficient energy conversion, nano to millimeter-sized structures are chosen for tailoring light guidance and charge carrier extraction via their optical and electrical characteristics. Ultrathin solar cells with integrated photonic nanostructures and micrometer-sized solar cells for operation under light concentration are two specific examples. Further possible applications in the field of energy conversion comprise e.g. the topics of solar fuels or thermoelectrics. Here, not only the opto-electronic functionalities of the nano to millimeter structures contribute, but also an accessible extended material space: the Chalcogenide material system constitutes the starting point with a broad potential for further development with respect to band gap variations but also in the direction of 2D materials. On the other hand, 3D nanostructures offer functionalities in other areas like phononic and piezoelectric materials. Via the multiple processes available in the cluster tool of the next generation a variety of structures becomes accessible which allows research on current relevant topics.