Scientists from Penn State University and the University of Southampton in the United Kingdom have developed a process to grow a single-crystal semiconductor inside the tunnel of a hollow optical fiber. The device adds new electronic capabilities to optical fibers, whose performance often is degraded at the interface between the fiber and the device.
The scientists used a high-pressure, fluid-liquid-solid approach to build the crystal inside the fiber. They deposited a tiny plug of gold inside the fiber by exposing a gold compound to laser light. Next, they introduced silane, a compound of silicon and hydrogen, in a stream of high-pressure helium. When the fiber was heated, the gold acted as a catalyst, decomposing the silane and thus allowing silicon to deposit as a single crystal behind the moving gold catalyst, forming a single-crystal wire inside the fiber.
The single-crystal device builds on research reported in 2006, where the scientists first demonstrated the ability to create an optical fiber comprising polycrystalline and amorphous semiconductor materials. The scientists hope to refine the optical fiber technology to reduce electrical losses at the fiber's ends for faster signal transmission.
