Project Details
Projekt
Towards transparent infrared optoelectronics
Applicant
Dr. Fabian Hartmann
Subject Area
Experimental Condensed Matter Physics
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 563850276
The project aims to address the fundamental challenge of reconciling the intrinsically conflicting properties of infrared transparency and electrical conductivity by developing a comprehensive theoretical framework and providing a proof-of concept experimental demonstrations. Infrared transparent conductive electrodes (TCEs) are critical for advanced applications such as infrared illumination, sensing, and imaging. However, achieving high optical transparency in the infrared range (> 3 μm) while maintaining superior electrical conductivity represents a profound scientific obstacle that has limited the effectiveness of all electrodes studied to date. This trade-off poses a major bottleneck for infrared optoelectronic devices, which require the simultaneous optimization of these two properties. Resolving this issue is particularly essential for enabling mid-wave infrared (MWIR) imaging, wireless communication (leveraging atmospheric transmission windows), and bio/chemical sensing and diagnostics that rely on selective molecular absorptions. These applications demand innovative solutions, including low-coherence, broadband light-emitting diodes (LEDs) and highly sensitive photodetectors (PDs), which remain unattainable with current TCE technology. In this project we will demonstrate experimentally for the first time an innovative approach with monolithic high-contrast one-dimensional grating integrated with metal (metalMHCG) as a solution. Despite being a one-dimensional subwavelength grating metalMHCG offers nearly total and polarization-independent light transmission and also unprecedently higher electrical conductivity compared to other TCEs. This mechanism demonstrates remarkable radiation transmission, effectively eliminating Fresnel reflection and nearly completely reducing metal absorption and reflection. Therefore metalMHCG can be integrated with diverse range of materials commonly used in optoelectronics, particularly high refractive index semiconductors, offering exceptional transparency required for surface emitting diodes (LEDs) and photodetectors (PDs). This breakthrough paves the way for revolutionary MWIR vertical LEDs and PDs arrays integrated on a single wafer, another key milestone of this project. By leveraging the transformative impact of metalMHCG, these devices will demonstrate significant advancements in emission and detection performance. With their versatile functionality, they have the potential to become the core components of next-generation infrared systems for sensing, diagnostics, imaging, and communication.
DFG Programme
Research Grants
International Connection
Poland
