Researchers at Michigan State University, East Lansing, report that by shooting an ultrafast laser pulse into a semiconductor, its properties change as if it had been chemically doped. Known as “photo-doping,” the laser pulses act like dopants that temporarily weaken the glue that binds charges and ions together. This allows new electronic phases to spontaneously form, producing new properties.
The technology involves varying the wavelengths and intensities of the laser pulses. The researchers were able to observe phases with different properties that are captured on the femtosecond timescale. “The material we studied is an unconventional semiconductor made of alternating atomically thin layers of metals and insulators,” said Chong-Yu Ruan, an associate professor of physics and astronomy who led the research effort at MSU. “This combination allows many unusual properties, including highly resistive and also superconducting behaviors to emerge, especially when doped.”
Philip Duxbury, a team member and chairman of the department of physics and astronomy, said ultrafast photo-doping “has potential applications that could lead to the development of next-generation electronic materials and possibly optically controlled switching devices made of undoped semiconductor materials.”
http://msutoday.msu.edu/news/2015/making-a-better-semiconductor/
