Nonequilibrium 1/f noise in platinum nanoparticle films

1/f noise spectra have been observed in platinum nanoparticle films deposited on SiO₂/Si substrates by laser ablation. Although all noise measurements were done in the linear region of the I-V characteristics, both equilibrium (ohmic) and nonequilibrium (nonohmic) behavior was observed in the dependence of the noise intensity on voltage (V). The nonequilibrium 1/f noise was found in some samples of smaller conductivity (small coverage). The sample with the smallest noise intensity features strong sublinear (V^0.2-0.37) nonequilibrium 1/f noise for voltages V<0.5V, while for V>0.5V the noise intensity is superlinear (V3.2). In the (20-300)K temperature range, the film resistance follows a T^-14/ dependence, specific to Mott´s phonon-assisted variable range hopping conduction.