Band alignments for tetracene (Tc), zinc phthalocyanine (ZnPc) and aluminum oxide (AlOx) deposited on a highly n-doped silicon surface (n+-Si). The red-dashed line indicates the position of the Fermi level (EF) of the system. The valence band maximum (EV) and highest occupied molecular orbital (HOMO) positions with respect to EFwere measured using UV photoelectron spectroscopy (UPS). The conduction band minimum (EC) and lowest unoccupied molecular orbital (LUMO) positions were calculated using the electronic band gaps from previous UPS and inverse photoemission spectroscopy measurements. The experimental energy resolution for measurements is typically 0.10 eV. The bulk ECand EVpositions of the doped silicon were calculated from the doping concentration. The black dashed lines show the energy of the lowest-lying state at the interface between the ZnPc layer andc-Si: the electron is located on ECand the hole is located on the HOMO of ZnPc. Nominal deposited thicknesses for the Tc, ZnPc, and AlOxlayers are listed.
