Interfacial electronic states of an anthracene derivative deposited on a SiO2 /Si substrate

The interfacial electronic states of an anthracene derivative (9,10-bis (methylthio) anthracene) on a SiO2/Si(100) substrate were studied using ultraviolet photoelectron spectroscopy (UPS). From the UPS measurements, the work function of the sample surface was found to decrease with increasing molecular coverage in the sub-monolayer range. It is concluded that an interfacial electronic dipole (about 0.34 eV) forms at the molecule/ SiO2 interface and decreases the effective work function.