Product Code: ICAL05_M705

Laser Thin Film Deposition on Plastic Substrates using Silicon Nanoparticles for Flexible Electronics
Authors:
Sachin Bet, University of Central Florida/ School of Optics and Photonics CREOL; Orlando Florida USA
Aravinda Kar, University of Central Florida/ CREOL; Orlando Florida USA
Nathaniel Quick, AppliCote Associates, LLC.; Orlando Florida USA
Presented at ICALEO 2005

The melting temperature of silicon nanoparticles decreases significantly compared to the melting temperature of bulk silicon when the particle size is less than 5 nm. This concept is utilized for reducing the processing temperatures to deposit thin polycrystalline silicon (c-Si) films on plastic substrates. An aqueous dispersion of 5 nm silicon nanoparticles was used as precursor. A Nd:YAG (1064nm wavelength) laser was used for deposition, melting and recrystallization. Experiments were carried in continuous wave mode in air as well as in argon atmosphere for obtaining a continuous recrystallized c-Si thin film on nickel substrates. Optimized parameters were utilized for obtaining c-Si films on plastic substrates. The process involved a film forming step and a recrystallization step. The films were characterized by optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Raman Spectroscopy. The oxygen content of laser air-treated film decreased with increasing both the laser power and the irradiation time during laser recrystallization. Laser argon-treated films showed comparatively reduced oxygen content. Raman spectroscopy showed a shift from amorphous to more crystalline phase with increasing the laser power and irradiation time during laser recrystallization. This was validated by the increasing number and size of silicon crystallites observed using SEM.