Laser wavelength and partial pressure effects on the formation of nanocrystalline Si

Si thin films on p-type (1 0 0) Si substrate have been fabricated by using pulsed laser deposition (PLD) with an Nd:YAG laser. Different laser wavelengths (λ=1064, 532, and 355 nm) are used to deposit Si nanocrystallites (nc-Si). The pressure of the environmental gas during deposition was varied from 1 to 3 Torr. After deposition, the Si thin films were annealed in N2 at 800 °C. Si nanocrystallites have shown strong blue photoluminescence (PL) band. Green and orange bands also have been observed. Si nanocrystallites grown by PLD showed visible PL strongly depending on the growth conditions such as laser wavelength and background gas pressure.