Formation of photoluminescent germanium nanostructures by femtosecond laser processing on bulk germanium: role of ambient gases

We present preparation of Ge nanostructures formed using by femtosecond laser pulse and origin of visible photoluminescence ( PL) properties. High intensity of incident laser energy gives rise to make oxidized layer to surface of Ge nanoparticle after irradiation. Moreover, size dependent Raman shift and PL spectrums are observed with different fluences and various process surroundings. It is noted that the oxidation of Ge nanoparticle formed ambient surroundings plays an important role of photoluminescence. (c) 2006 Optical Society of America.