Indium and gallium selenide nanofilms: spray-ILGAR fabrication and phase characterization towards stable interfaces and devices (INGA the SNAIL)

• Applicant: Professorin Dr. Martina Schmid
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551988047

Miniaturization and resource efficiency are two key aspects of future technology development. They are key challenges in many fields like micro- and optoelectronics, sensing and actuating, energy generation and storage. Microelectronics, for example, is at a turning point in its history as the down-scaling of silicon technology is hitting its limits. Novel materials may be a solution and the combination in integrated system design is an upcoming puzzle to be resolved. Innovations are sought and materials with intriguing characteristics at the smallest scales hold great promise: 2D materials. Graphene is certainly the most researched 2D material with outstanding charge carrier mobility but a fundamental lack of band gap. Transition metal dichalcogenides reveal similar 2D behavior but very distinct semiconducting properties arising from the tunability of their band gaps. Whereas MoS(e)2 and WS(e)2 are commonly in focus, group IIIA metal chalcogenide 2D materials (G3AMC2DMs) are significantly less researched despite being equally promising in terms of tuneability of properties, and high carrier mobility. Even more, they offer direct band gaps and different intrinsic doping types. The classical fields of application include transistors and photodetectors but also thermoelectric, piezoelectric, and lately ferroelectric devices are reported. The deliberate fabrication of the various possible phases and with it the targeted adjustment of distinct material properties is a prerequisite for the efficient integration of these 2D materials. A related key challenge is the direct large-scale fabrication, where standard exfoliation techniques struggle. We therefore propose the development of an aerosol-assisted chemical vapor deposition process - spray-ILGAR - as a cheap and scalable method for indium selenide and gallium selenide 2D material growth. Simultaneously, we focus on flexible substrates to make ideal use of the inherent property of mechanical flexibility the 2D materials offer. The combination of different 2D materials in e.g. heterojunctions and the consideration of (controlled) oxidation or rather its exploitation in the process of device integration are further topics deserving detailed investigations and profound understanding. Interface formation is a central aspect of establishing these materials in different devices and applications. By researching the little-established but highly promising G3AMC2DMs with a low-cost and proven scalable fabrication approach, we target the provision of resource-efficient materials for future miniaturization of various technologies.

• DFG Programme: Research Grants