Abstract
It is researched that low temperature preparing process of thin film phosphors by laser annealing. Using phosphor is SrGa_2S_4:Eu^<2+>. Preparing process is that Ga_2S_3:Eu (1mol%) and SrS:Eu (2mol%) pellets were evaporated by two electron beams, and deposited on substrates. After deposition, pre-annealing at 500℃ is carried out, then Nd:YAG (355nm) laser is irradiated. In this study, to consider the preparation mechanism of SrGa_2S_4:Eu^<2+> by 355nm laser annealing, spectral transmittance of SrS:Eu and Ga_2S_3:Eu thin films were measured, and simulation of thermal distribution was carried out. At 355nm, transmittance of SrS is higher than Ga_2S_3, and according to simulation result, it was guessed that Ga_2S_3 absorbed laser energy mainly and heated. SrGa_2S_4:Eu^<2+> thin films were prepared by 355nm laser at 10Hz change from 8kHz, to know the relationship between laser frequency and influence to preparation of thin film by laser annealing. On 10Hz laser annealed samples have very few luminance, and it was found that these are almost amorphous by XRD result. It is guessed that laser of low frequency can not obtain hearings on each pulse, due to wide pulse length.
