A new organic complex thin film for ultra-high-density data storage with a scanning tunneling microscope

A new organic complex, tetrathiafulvalene/m-nitrobenzylidene propanedinitrile (TTF/m-NBP), was prepared to use as an ultra-high-density data-storage medium. A nanometer-scale recording technique was demonstrated with a scanning tunneling microscope (STM) under ambient conditions. The organic complex thin film was fabricated by using a vacuum thermal deposition method. The results of Fourier transform infrared spectra showed that the structure of the organic complex thin film was the same as that of a complex crystal. Data were recorded by applying voltage pulses between the tip and the substrate. Current-voltage (I-V) curves measured by the STM showed that the conductance of the recorded region is much higher than that of the unrecorded region, which indicated that the data were recorded by a local change of the electrical property of the film. The smallest recorded mark was 1.1 nm in diameter and the width of the pulse voltage has an influence upon the diameter of the recording marks.