[20p-W321-1~13] Progress in studies on laser-processing employing liquid media

[20p-W321-7] High-yield preparation and luminescence-color control of colloidal silicon nanocrystals by pulsed-laser irradiation of porous silicon

〇Toshihiro Nakamura¹, Ze Yuan², Sadao Adachi¹ (1.Gunma Univ., 2.Tsukuba Univ.)

Keywords:semiconductor nanocrystals,photoluminescence,laser ablation

Colloidal Si nanocrystal (Si-NC), which is nanometer sized (~1–10 nm) crystalline Si particle, is known to exhibit a size tunable and efficient visible luminescence at room temperature due to the quantum confinement effect. Because of its environmental friendliness and low cost, colloidal Si-NC is a promising material for future light-emitting devices and biomedical applications. Various preparation techniques for colloidal Si-NC, such as wet-chemical synthesis and high-temperature thermal processing have been developed. Pulsed laser irradiation of bulk Si in liquid is one of simple methods to produce colloidal luminescent Si-NC solution without any unnecessary reagent. However, yield of the nanoparticle production is usually low because of the use of a high-power density laser light. Furthermore, the control of its size is essentially difficult. Here, we demonstrate the high-yield preparation and the size control (i.e., emission-color) of luminescent colloidal Si-NC by pulsed laser irradiation of porous Si in an organic solution.