Unraveling Electron Dynamics in p-type Indium Phosphide (100): A Time-Resolved Two-Photon Photoemission Study

• DOI: 10.1021/jacs.3c12487
• Publication Date: 2024-03-19T12:49:45Z
• Authors: Jonathan Diederich; Jennifer Velasque...; Mohammad Amin Zar...; Isaac Azahel Ruiz...; Agnieszka Paszuk; Rachele Sciotto; Christian Höhn; Klaus Schwarzburg; David Ostheimer; Rainer Eichberger; Wolf Gero Schmidt; Thomas Hannappel; Roel van de Krol; Dennis Friedrich
• Keywords: Surface States; Indium phosphide; Inverse photoemission spectroscopy; Quasi Fermi level; Surface Photovoltage

Renewable ("green") hydrogen production through direct photoelectrochemical (PEC) water splitting is a potential key contributor to the sustainable energy mix of future. We investigate indium phosphide (InP) as reference material among III–V semiconductors for PEC and photovoltaic (PV) applications. The p(2 × 2)/c(4 2)-reconstructed phosphorus-terminated p-doped InP(100) (P-rich p-InP) surface focus our investigation. employ time-resolved two-photon photoemission (tr-2PPE) spectroscopy study electronic states near band gap with an emphasis on normally unoccupied conduction that are inaccessible conventional single-photon emission methods. shows complexity p-InP structure reveals presence at least nine distinct between valence edge vacuum energy, including state, defect state pinning Fermi level, six resonances within band, well cluster about 1.6 eV above CBM, identified bulk-to-surface transition. Furthermore, we determined decay constants five states, enabling us track electron relaxation bulk bands. This comprehensive understanding dynamics in p-InP(100) lays foundation further exploration engineering enhance properties applications p-InP-based III–V-compounds for, e.g., efficient cost-effective highly PV cells.