Origin of indium-[perylene-3,4,9,10-tetracarboxilic dianhydride] interfacestates studied by outermost surface spectroscopy using metastable atoms - art. no. 115204

Metastable atom electron spectra (MAES) and ultraviolet photoelectron spect ra (UPS) of indium-[perylene-3,4,9,10-tetracarboxilic dianhydride (PTCDA)] system prepared on a MoS2 single crystal substrate were measured as a funct ion of the In overlayer thickness (Theta (In)). As observed by a previous U PS experiment, a new band was observed in the original PTCDA energy gap reg ion even by the MAES which detects the outermost surface selectively. The T heta (In) dependence of this new band intensity measured by the MAES gives a maximum at Theta (In)similar to1 Angstrom, suggesting that four In atoms are reacting with one PTCDA molecule at the C=O parts. From the result of t he density functional theory (DFT) methods and the enhanced intensity of th e new band in the MAES, it was concluded that the new band originates from pi state consisting of In 5pz AO's.