グリオキシル酸コバルト錯体の調製とフェムト秒レーザパルス照射によるコバルト析出

抄録

Co patterns were fabricated by using femtosecond laser pulse-induced thermochemical reduction of glyoxylic acid Co complex. Glyoxylic acid Co complex was synthesized by mixing CoSO₄·7H₂O and glyoxylic acid, following that the complex was dissolved in 2-aminoethanol/ethanol. Femtosecond laser pulses were focused and irradiated to the glyoxylic acid Co complex films spin-coated on glass substrates to form patterns. The minimum line width was 4 µm, which was larger than the focal spot diameter, indicating that the precipitation was induced by thermochemical reduction. The crystal structures of the patterns which were fabricated at high scanning speed, 10 and 20 mm/s, exhibited Co(fcc), suggesting that the precipitated Co nanoparticles from glyoxylic acid Co complex were sintered without the phase transition to Co(hcp). In contrast, CoO patterns were formed at low scanning speed, 1 mm/s. These results suggested that precipitated Co was oxidized by ambient oxygen in air by irradiating excess laser pulse energy. The metal Co direct writing technique is useful for printing of various microdevices.