Electrical Properties of CuI Thin Films and Bulk Material and Fabrication of CuI-based Devices

• Applicant: Dr. Holger von Wenckstern
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 403159832

The primary objective of the proposal is to develop electronic circuit elements using p-type CuI or related alloys as the active material. Secondary objectives include characterizing the electrical properties of metal halide thin films, single crystals and heterostructures, investigating defect states by space charge layer spectroscopy, determining doping limits, and identifying the origin of the surface conductivity commonly observed for CuI. An important finding of the first funding period of the research group is that the electrical properties of CuI films and crystals, as well as the position of their surface Fermi level, depend sensitively on the presence of oxygen or moisture. This significantly affected the performance of devices previously fabricated under ambient conditions. Therefore, a technical solution to achieve the central objective of this proposal is to establish a complete in-situ fabrication chain for the growth of single crystalline layers, heterostructures and the realization of active devices that does not require vacuum break prior to full encapsulation, which is enabled by selective surface deposition. For this purpose, a shadow mask system is installed in our CuI PLD chamber, which allows to define the location of material deposition in the sub-mm range (in the best case below 100µm). This fully vacuum-based approach ensures that the intended goals can be achieved.

• DFG Programme: Research Units
• Subproject of: FOR 2857: Copper Iodide as Multifunctional Semiconductor