Data storage with 0.7 nm recording marks on a crystalline organic thin film by a scanning tunneling microscope

Abstract
Ultrahigh density data storage on a novel organic thin film by scanning tunneling microscope(STM) under ambient conditions is demonstrated. The material, N-(3-nitrobenzylidene)p-phenylenediamine (NBPDA), is used for preparing thin film by vacuum evaporation method. Crystalline NBPDA films with electrical bistability are obtained by this method. Recording experiment on the films is made by applying voltage pulses between the STM tip and substrate. The recorded marks are 0.7 nm in size, corresponding to a storage density of 10 14 bit/cm 2 . Current–voltage characteristicmeasurement shows that the resistance of the unrecorded region of the NBPDA films is much higher than that of the recorded region. The mechanism of recording is discussed.