Scientists develop method to grow ultrathin semiconductors on electronics

A team of materials scientists at Rice University in Houston, Texas, has developed a new way to grow ultrathin semiconductors directly onto electronic components. The method, described in a study published in ACS Applied Electronic Materials, could help streamline the integration of two-dimensional materials into next-generation electronics, neuromorphic computing and other technologies demanding ultrathin high-speed semiconductors, according to an online news post by Rice.

The researchers used chemical vapor deposition (CVD) to grow tungsten diselenide, a 2D semiconductor, directly onto patterned gold electrodes. They next demonstrated the approach by building a functional, proof-of-concept transistor. Unlike conventional techniques that require transferring fragile 2D films from one surface to another, the Rice team’s method eliminates the transfer process entirely.

“This is the first demonstration of a transfer-free method to grow 2D devices,” said Sathvik Ajay Iyengar, a doctoral student at Rice and a first author on the study along with Rice doctoral alumnus Lucas Sassi. “This is a solid step toward reducing processing temperatures and making a transfer-free, 2D semiconductor-integration process possible.”

Conventional device fabrication requires growing the 2D semiconductor separately, usually at very high temperatures, then transferring it using a series of steps. While 2D materials promise to outperform silicon in certain metrics, turning their lab-scale promise into industry-relevant applications has proven difficult — in large part due to the fragility of the materials during the transfer process.

The transfer process can degrade the material and damage its performance, said Iyengar, who is part of Pulickel Ajayan’s research group at Rice.

The Rice team optimized the precursor materials to lower the synthesis temperature of the 2D semiconductor and showed that it grows in a controlled, directional manner, the online post said.

“Understanding how these 2D semiconductors interact with metals, especially when grown in situ, is really valuable for future device fabrication and scalability,” said Pulickel Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor of Engineering and professor of materials science and nanoengineering.

The success of the method lies in the strong interaction between the metal and the 2D material during growth.

“The absence of reliable, transfer-free methods for growing 2D semiconductors has been a major barrier to their integration into practical electronics,” said Rice doctoral alumnus Lucas Sassi. “This work could unlock new opportunities for using atomically thin materials in next-generation transistors, solar cells and other electronic technologies.”