The Thin Films Of Silicon Nanocrystals With Luminescent Properties

Silicon is a kind of excellent semiconductor material, is one of the core material of microelectronics. But it is not a fine luminescent material. The photoluminescence (PL) will be obtained by excitation only when the size of silicon partials reduced to a certain value. The photoluminescence (PL) of silicon nano-crystals film is our constant aim in the development from micro-electron technique to optoelectronic integrated technique.A brand new method called vertical pulsed laser deposition has been introduced in this paper. We adjust laser beam to penetrate a transparent substrate that is not the laser-absorbing material, to reach the silicon target. (A piece of thin glass has been used as substrate in my paper, because it can't absorb the energy of laser beam.) The target surface is eroded, plasma sprays out and finally deposits on the surface of the transparent substrate. Besides, the film on the surface of glass has been successfully transferred to another silicon wafer. Then three kinds of films are acquired: silicon film on the surface of glass, the film on silicon target and transferred film on another silicon substrate.The microstructure of the films has been detected by SEM, XRD, TEM and electronic microscope. We find all the silicon film is made of nano-crystals whose diameter is less than 100nm. Their size, thickness and morphology depend partly on parameter of experiment. Fluorescence is got by fluorescent spectrometry. We find the fluorescence-emission of silicon film on glass is around 420nm, 485nm and 530nm; the fluorescence-emission of silicon target is around 424nm; the fluorescence-emission of the transferred silicon film is around 400nm.