Use of an asymmetric pulse profile for higher crystalline volumes from excimer laser crystallization of amorphous silicon

An excimer laser is used to crystallize amorphous silicon on glass to nanocrystalline silicon, yielding higher crystalline volumes than reported earlier, by modifying the laser pulse profile used for crystallization at a given energy density. An asymmetric, shorter pulse profile, as opposed to the conventional Gaussian profile retains the desirable gradual leading edge of the Gaussian pulse for controlled evolution of hydrogen, while increasing the peak energy. The resultant films show an increased surface roughness along with higher crystalline volumes, which may be beneficial for photovoltaics and electron field emission cold cathodes. (c) 2007 American Institute of Physics.