Electronic structure and band alignment of 9,10-phenanthrenequinone passivated silicon surfaces

In this work we demonstrate that the room-temperature deposition of the organic molecule 9,10-phenanthrenequinone (PQ) reduces the surface defect density of the silicon (100) surface by chemically bonding to the surface dangling bonds. Using various spectroscopic measurements we have investigated the electronic structure and band alignment properties of the PQ/Si interface. The band-bending at the PQ-passivated silicon surface is negligible for both n- and p-type substrates, demonstrating a low density of surface defects. Finally we show that PQ forms a semiconducting wide-bandgap type-I heterojunction with silicon. ► 9,10-phenanthrenequinone (PQ) passivates dangling bonds on the silicon(100) surface. ► PQ is deposited at room temperature but leads to electronically ideal Si surfaces. ► PQ reacts with Si surface atoms to form a 9,10-dihydroxyphenanthrene adduct. ► PQ/Si interface is a staggered (type-I) heterojunction.