Electron relaxation dynamics at the In-rich (100) surface of InP

The temporal relaxation of optically excited electrons at the In-rich reconstructed InP(100) surface was studied using time-resolved two-photon-photoemission spectroscopy (TR-2PPE). High-energy carriers were generated at laser pump energies chosen to populate hot electron bulk states or the well known C 2 surface state via resonant direct optical excitation. The different relaxation pathways arising from these population schemes involve Γ-L-Γ intervalley scattering and the transient occupation of an additional surface state, C 1 . The dynamics of these processes were recorded with a novel experimental setup using two ultra-low power 150 KHz repetition rate sub-20 fs NOPAs enabling two-colour pump-probe experiments in the linear regime. These experiments provide useful information in understanding the dynamics of devices on the basis of this semiconductor medium such as solar cells and high-speed switching circuits.