Microstructure-Based Optimization of Pulsed Laser Deposited CuI Thin Films

• Applicants: Professor Dr. Michael Lorenz; Dr. Susanne Selle
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 403159832

Based on the surprisingly promising results in the first funding period, the project work at Universität Leipzig will now focus exclusively on pulsed laser deposition (PLD) of CuI-based heterostructures. However, the portfolio of state-of-the-art microstructural analysis techniques at Fraunhofer IMWS in Halle is not only limited to PLD-grown films, but is used for characterization of all types of CuI samples within the frame of the whole Research Unit. In this way, different growth methods can be compared, for example with respect to adhesion properties of CuI films. In addition to electron microscopical methods, delivering superior lateral resolution (TEM), yet as well rather large screening areas (SEM, EBSD), surface analysis including ToF-SIMS and nanoindentation will be applied. Thereby, the latter represents a promising technique for mechanical characterization. PLD allows to control the p-type carrier concentration and Hall mobility, is highly flexible in doping and alloying of CuI, and provides single-crystalline films without rotation domains. The demonstration of CuI-based electronic devices is supported by the following efforts: (a) by exploring the first nucleation stages and various dopants, (b) by developing capping layers to further enhance the electrical stability of CuI, and (c) by lift-off of free-standing CuI templates for large-area CuI single crystals. Complete device heterostructures with individual in-situ structuring by shadow masks will be realized together with project P05.

• DFG Programme: Research Units
• Subproject of: FOR 2857: Copper Iodide as Multifunctional Semiconductor
• Co-Investigators: Professor Dr. Marius Grundmann; Professor Dr. Thomas Höche; Dr. Christian Patzig