@article{60580,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>AlInP (001) is widely utilized as a window layer in optoelectronic devices, including world‐record III‐V multi‐junction solar cells and photoelectrochemical (PEC) cells. The chemical and electronic properties of AlInP (001) depend on its surface reconstruction, which impacts its interaction with electrolytes in PEC applications and passivation layers. This study investigates AlInP (001) surface reconstructions using density functional theory and experimental methods. Phosphorus‐rich (P‐rich) and indium‐rich (In‐rich) AlInP surfaces are prepared with in situ monitoring of the process by reflection anisotropy (RA) spectroscopy and confirmed by low‐energy electron diffraction and photoemission spectroscopy. The experimental RA spectra closely match the theoretical predictions obtained by solving the Bethe–Salpeter equation. It is shown that missing hydrogen on P‐rich surfaces and formation of In–In 1D atomic chains on In‐rich surfaces introduce mid‐gap surface states that pin the Fermi level and induce band bending. Time‐resolved two‐photon photoemission measurements reveal ultrafast near‐surface electron dynamics for both P‐rich and In‐rich surfaces, demonstrating photoexcited electrons reaching the surface conduction band minimum and relaxing to mid‐gap surface states on about hundreds of fs. This work provides the most extensive AlInP surface analysis to date, allowing for more targeted surface and interface engineering, which is crucial for the optimization and design of III‐V heterostructures.</jats:p>}},
  author       = {{Zare Pour, Mohammad Amin and Shekarabi, Sahar and Ruiz Alvarado, Isaac Azahel and Diederich, Jonathan and Gao, Yuyings and Paszuk, Agnieszka and Moritz, Dominik C. and Jaegermann, Wolfram and Friedrich, Dennis and van de Krol, Roel and Schmidt, Wolf Gero and Hannappel, Thomas}},
  issn         = {{1616-301X}},
  journal      = {{Advanced Functional Materials}},
  publisher    = {{Wiley}},
  title        = {{{Exploring Electronic States and Ultrafast Electron Dynamics in AlInP Window Layers: The Role of Surface Reconstruction}}},
  doi          = {{10.1002/adfm.202423702}},
  year         = {{2025}},
}

@article{58642,
  abstract     = {{We present a cost-effective self-assembly method to fabricate low-density dimer NPs in an NPoM architecture, using the M13 phage as a spacer layer. This will enable the development of dynamic plasmonic devices and advanced sensing applications.}},
  author       = {{Devaraj, Vasanthan and Ruiz Alvarado, Isaac Azahel and Lee, Jong-Min and Oh, Jin-Woo and Gerstmann, Uwe and Schmidt, Wolf Gero and Zentgraf, Thomas}},
  issn         = {{2055-6756}},
  journal      = {{Nanoscale Horizons}},
  pages        = {{537--548}},
  publisher    = {{Royal Society of Chemistry (RSC)}},
  title        = {{{Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror}}},
  doi          = {{10.1039/d4nh00546e}},
  volume       = {{10}},
  year         = {{2025}},
}

@article{61351,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>The interaction of water molecules with semiconductor surfaces is relevant to various optoelectronic phenomena and physicochemical processes. Despite advances in fundamental understanding of water‐exposed surfaces, the detailed time‐ and energy‐resolved behavior of excited electrons remains largely unexplored. Here, the effects of water exposure on the near‐surface electron dynamics of phosphorus‐terminated p(2×2)/c(4×2)‐reconstructed indium phosphide (100) (P‐rich InP) are studied experimentally and matched to theoretical calculations. The P‐rich InP surface, consisting of H‐passivated P‐dimers, serves as a model for other P‐containing III‐V semiconductors such as gallium phosphide (GaP) or aluminum indium phosphide (AlInP). Electron dynamics near the surface are probed with femtosecond resolution using time‐resolved two‐photon photoemission (tr‐2PPE), a pump‐probe spectroscopic technique. Pulsed water exposure preserves electronic states and significantly increases lifetimes at the conduction band minimum (CBM). Density‐functional theory (DFT) calculations attribute these findings to suppression of surface vibrational modes in the top P‐layer by water exposure, reducing electronic transition probabilities of near‐band‐gap surface states. The results suggest that many near‐surface state lifetimes reported in ultra‐high vacuum may change significantly upon electrolyte exposure. These states may thus contribute more strongly to surface reactions than traditionally assumed. Demonstrating this effect for the technologically relevant P‐rich InP surface opens new opportunities in this underexplored area of surface electrochemistry.</jats:p>}},
  author       = {{Diederich, Jonathan and Paszuk, Agnieszka and Ruiz Alvarado, Isaac Azahel and Krenz, Marvin and Zare Pour, Mohammad Amin and Babu, Diwakar Suresh and Velazquez Rojas, Jennifer and Höhn, Christian and Gao, Yuying and Schwarzburg, Klaus and Ostheimer, David and Eichberger, Rainer and Schmidt, Wolf Gero and Hannappel, Thomas and de Krol, Roel van and Friedrich, Dennis}},
  issn         = {{2196-7350}},
  journal      = {{Advanced Materials Interfaces}},
  number       = {{16}},
  publisher    = {{Wiley}},
  title        = {{{Ultrafast Electron Dynamics at the Water‐Modified InP(100) Surface}}},
  doi          = {{10.1002/admi.202500463}},
  volume       = {{12}},
  year         = {{2025}},
}

@inproceedings{61352,
  author       = {{Devaraj, Vasanthan and Ruiz Alvarado, Isaac Azahel and Lee, Jongmin and Oh, Jin-Woo and Gerstmann, Uwe and Schmidt, Wolf Gero and Zentgraf, Thomas}},
  booktitle    = {{2025 Conference on Lasers and Electro-Optics Europe &amp;amp; European Quantum Electronics Conference (CLEO/Europe-EQEC)}},
  publisher    = {{IEEE}},
  title        = {{{Dynamic and Reversible Plasmonic Nanogaps From Isolated Dimer Nanoparticles via Self-Assembly}}},
  doi          = {{10.1109/cleo/europe-eqec65582.2025.11109762}},
  year         = {{2025}},
}

@article{60581,
  abstract     = {{<jats:title>Abstract</jats:title>
               <jats:p>The natural band alignments between indium phosphide and the main dioxides of titanium, i.e. rutile, anatase, and brookite as well as amorphous titania are calculated from the branch-point energies of the respective materials. Irrespective of the titania polymorph considered, type-I band alignment is predicted. This may change, however, in dependence on the microscopic interface structure: supercell calculations for amorphous titania grown on P-rich InP(001) surfaces result in a titania conduction band that nearly aligns with that of InP. Depending on the interface specifics, both type-I band and type-II band alignments are observed in the simulations. This agrees with recent experimental findings.</jats:p>}},
  author       = {{Ruiz Alvarado, Isaac Azahel and Dreßler, Christian and Schmidt, Wolf Gero}},
  issn         = {{0953-8984}},
  journal      = {{Journal of Physics: Condensed Matter}},
  number       = {{7}},
  publisher    = {{IOP Publishing}},
  title        = {{{Band alignment at InP/TiO<sub>2</sub> interfaces from density-functional theory}}},
  doi          = {{10.1088/1361-648x/ad9725}},
  volume       = {{37}},
  year         = {{2024}},
}

@article{60582,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>The current efficiency records for generating green hydrogen via solar water splitting are held by indium phosphide (InP)‐based photo‐absorbers, protected by TiO<jats:sub>2</jats:sub> layers grown through atomic layer deposition (ALD). InP is also a leading material for photonic integrated circuits and computing, where ultrafast near‐surface behavior is key. A previous study described electronic pathways at the phosphorus‐rich (P‐rich) surface of p‐doped InP(100) using time‐resolved two‐photon photoemission (tr‐2PPE) spectroscopy. Here, the intricate electron pathways of the P‐rich InP surface modified with ALD‐deposited TiO<jats:sub>2</jats:sub> are explored. Photoexcited bulk InP electrons migrate through a bulk‐to‐surface transition cluster of states and surface states and inject into the TiO<jats:sub>2</jats:sub> conduction band (CB). Energy levels and occupation dynamics of CB states in P‐rich InP and TiO<jats:sub>2</jats:sub> adlayers are observed, with discrete states preserved up to 10 nm TiO<jats:sub>2</jats:sub> deposition. Thermalization lifetimes of excited electrons &gt; 0.8 eV above the InP conduction band minimum (CBM) are preserved for layer thicknesses up to 2.5 nm. Annealing at 300 °C to achieve crystalline TiO<jats:sub>2</jats:sub> reconstructions destroys interfacial states, affecting charge transfer. These observations enable innovative engineering of the P‐rich InP/TiO<jats:sub>2</jats:sub> heterointerface, opening new possibilities for studying hot‐carrier extraction, adsorbate effects, surface plasmons, and improving photovoltaic and PEC water‐splitting devices.</jats:p>}},
  author       = {{Diederich, Jonathan and Rojas, Jennifer Velazquez and Paszuk, Agnieszka and Pour, Mohammad Amin Zare and Höhn, Christian and Ruiz Alvarado, Isaac Azahel and Schwarzburg, Klaus and Ostheimer, David and Eichberger, Rainer and Schmidt, Wolf Gero and Hannappel, Thomas and van de Krol, Roel and Friedrich, Dennis}},
  issn         = {{1616-301X}},
  journal      = {{Advanced Functional Materials}},
  number       = {{49}},
  publisher    = {{Wiley}},
  title        = {{{Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO<sub>2</sub> Interface}}},
  doi          = {{10.1002/adfm.202409455}},
  volume       = {{34}},
  year         = {{2024}},
}

@article{54866,
  author       = {{Diederich, Jonathan and Velasquez Rojas, Jennifer and Zare Pour, Mohammad Amin and Ruiz Alvarado, Isaac Azahel and Paszuk, Agnieszka and Sciotto, Rachele and Höhn, Christian and Schwarzburg, Klaus and Ostheimer, David and Eichberger, Rainer and Schmidt, Wolf Gero and Hannappel, Thomas and van de Krol, Roel and Friedrich, Dennis}},
  issn         = {{0002-7863}},
  journal      = {{Journal of the American Chemical Society}},
  number       = {{13}},
  pages        = {{8949--8960}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Unraveling Electron Dynamics in p-type Indium Phosphide (100): A Time-Resolved Two-Photon Photoemission Study}}},
  doi          = {{10.1021/jacs.3c12487}},
  volume       = {{146}},
  year         = {{2024}},
}

@article{54855,
  abstract     = {{<jats:p>Density-functional theory calculations on P-rich InP(001):H surfaces are presented. Depending on temperature, pressure and substrate doping, hydrogen desorption or adsorption will occur and influence the surface electronic properties. For p-doped samples, the charge transition levels of the P dangling bond defects resulting from H desorption will lead to Fermi level pinning in the lower half of the band gap. This explains recent experimental data. For n-doped substrates, H-deficient surfaces are the ground-state structure. This will lead to Fermi level pinning below the bulk conduction band minimum. Surface defects resulting from the adsorption of additional hydrogen can be expected as well, but affect the surface electronic properties less than H desorption.</jats:p>}},
  author       = {{Sciotto, Rachele and Ruiz Alvarado, Isaac Azahel and Schmidt, Wolf Gero}},
  issn         = {{2571-9637}},
  journal      = {{Surfaces}},
  number       = {{1}},
  pages        = {{79--87}},
  publisher    = {{MDPI AG}},
  title        = {{{Substrate Doping and Defect Influence on P-Rich InP(001):H Surface Properties}}},
  doi          = {{10.3390/surfaces7010006}},
  volume       = {{7}},
  year         = {{2024}},
}

@article{49634,
  author       = {{Ruiz Alvarado, Isaac Azahel and Zare Pour, Mohammad Amin and Hannappel, Thomas and Schmidt, Wolf Gero}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Structural fingerprints in the reflectance anisotropy of AlInP(001)}}},
  doi          = {{10.1103/physrevb.108.045410}},
  volume       = {{108}},
  year         = {{2023}},
}

@article{37656,
  author       = {{Glahn, Luis Joel and Ruiz Alvarado, Isaac Azahel and Neufeld, Sergej and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Ostheimer, David and Shekarabi, Sahar and Romanyuk, Oleksandr and Moritz, Dominik Christian and Hofmann, Jan Philipp and Jaegermann, Wolfram and Hannappel, Thomas and Schmidt, Wolf Gero}},
  issn         = {{0370-1972}},
  journal      = {{physica status solidi (b)}},
  keywords     = {{Condensed Matter Physics, Electronic, Optical and Magnetic Materials}},
  number       = {{11}},
  publisher    = {{Wiley}},
  title        = {{{Clean and Hydrogen‐Adsorbed AlInP(001) Surfaces: Structures and Electronic Properties}}},
  doi          = {{10.1002/pssb.202200308}},
  volume       = {{259}},
  year         = {{2022}},
}

@article{37710,
  author       = {{Ruiz Alvarado, Isaac Azahel and Schmidt, Wolf Gero}},
  issn         = {{2470-1343}},
  journal      = {{ACS Omega}},
  keywords     = {{General Chemical Engineering, General Chemistry}},
  number       = {{23}},
  pages        = {{19355--19364}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Water/InP(001) from Density Functional Theory}}},
  doi          = {{10.1021/acsomega.2c00948}},
  volume       = {{7}},
  year         = {{2022}},
}

@article{37681,
  author       = {{Moritz, Dominik Christian and Ruiz Alvarado, Isaac Azahel and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Frieß, Tilo and Runge, Erich and Hofmann, Jan P. and Hannappel, Thomas and Schmidt, Wolf Gero and Jaegermann, Wolfram}},
  issn         = {{1944-8244}},
  journal      = {{ACS Applied Materials &amp; Interfaces}},
  keywords     = {{General Materials Science}},
  number       = {{41}},
  pages        = {{47255--47261}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{P-Terminated InP (001) Surfaces: Surface Band Bending and Reactivity to Water}}},
  doi          = {{10.1021/acsami.2c13352}},
  volume       = {{14}},
  year         = {{2022}},
}

@article{37714,
  author       = {{Karmo, Marsel and Ruiz Alvarado, Isaac Azahel and Schmidt, Wolf Gero and Runge, Erich}},
  issn         = {{2470-1343}},
  journal      = {{ACS Omega}},
  keywords     = {{General Chemical Engineering, General Chemistry}},
  number       = {{6}},
  pages        = {{5064--5068}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Reconstructions of the As-Terminated GaAs(001) Surface Exposed to Atomic Hydrogen}}},
  doi          = {{10.1021/acsomega.1c06019}},
  volume       = {{7}},
  year         = {{2022}},
}

@article{22009,
  author       = {{Ruiz Alvarado, Isaac Azahel and Karmo, Marsel and Runge, Erich and Schmidt, Wolf Gero}},
  issn         = {{2470-1343}},
  journal      = {{ACS Omega}},
  pages        = {{6297--6304}},
  title        = {{{InP and AlInP(001)(2 × 4) Surface Oxidation from Density Functional Theory}}},
  doi          = {{10.1021/acsomega.0c06019}},
  year         = {{2021}},
}