Laser wavelength effect on the light emission properties of nanocrystalline Si on Si substrate fabricated by pulsed laser deposition

Nanocrystalline Si (nc-Si) on p-type Si substrate has been fabricated by pulsed laser deposition (PLD) technique using a Nd:YAG laser with different wavelengths of 355, 532, and 1064 nm. Basal pressure was maintained at 1×10−5 Torr. Si nanocrystalline thin films are fabricated in 1–3 Torr He ambient. After deposition, nc-Si has been annealed in N2 gas. Strong violet-indigo luminescence from Si nanocrystallites has been observed at room temperature by photoluminescence (PL). Its peak energies shift to green when the wavelength of pulsed laser is increased from 355 to 1064 nm. As increasing environmental gas pressure, weak green and red emissions from annealed nc-Si was also observed by PL.