The Need

Two-Dimensional van der Waals materials have shown great promise for a variety of electronic, optoelectronic, sensing, and energy conversion applications. To meet the need for clean energy production, photovoltaic cells and thermoelectric modules require advanced semiconducting materials that increase the efficiency of light and heat capture. These materials must be durable and thermally resistant to allow for a reasonable lifespan. Silicon is widely recognized as the standard for industrial semiconducting applications, but current technologies have exhausted the feasible limits of miniaturization and speed. Therefore, scientists must either develop alternative semiconducting materials or augment current silicon semiconductors.

The Technology

Researchers at The Ohio State University, led by Dr. Joshua Goldberger, have developed a simple one-step reaction of calcium germanium and methyl iodide that creates a methylated germanane film. This methylated film exhibits increased thermal resistance compared to hydrogenated germanane. Replacing the termination group in GeH with CH₃ increases the band gap from 0.1 eV to 1.7 eV and produces band edge fluorescence with a quantum yield of 0.2% with little dependence on layer thickness. Finally, germanane begins to decompose at temperatures of approximately 75 ^oC, but the methylated variety is resilient up to 250 ^oC.

Commercial Applications

• Thermoelectric materials: industrial atomization, electronics, optoelectronics, sensing equipment, energy conversion

Benefits/Advantages

• Faster mobilities and faster transistors compared to Germanium
• Direct band gap allows for use in photovoltaics, lasers, and LEDs
• Offers advantages in fictionalization and processing
• High specificity sensing and surface-tuning of band structure
• Produces higher voltages when absorbing photons from sunlight, which promises greater conversion efficiency for photovoltaic devices
• CH₃ termination increases the resistance to oxidation, which creates a more resilient, longer lasting material