Clean and Hydrogen-Adsorbed AlInP(001) Surfaces: Structures and Electronic Properties Luis Joel Glahn, Isaac Azahel Ruiz Alvarado,* Sergej Neufeld, Mohammad Amin Zare Pour, Agnieszka Paszuk, David Ostheimer, Sahar Shekarabi, Oleksandr Romanyuk, Dominik Christian Moritz, Jan Philipp Hofmann, Wolfram Jaegermann, Thomas Hannappel, and Wolf Gero Schmidt 1. Introduction III–V compound semiconductors are important for various electronic and optoelectronic applications, for example, high-electron-mobility transistors, light- emitting diodes, photodetectors, electro- optic modulators, and frequency-mixing components. Solar cells made of III–V semiconductors reach the highest efficien- cies of any photovoltaic technology so far.[1] The AlxIn1�xP (AlInP) material sys- tem is frequently used as window layer in solar cells, due to its favorable combination of chemical stability, sufficiently wide bandgap, and high-quality heteroepitaxial interfaces with many absorbers.[2] In this context, the Fermi-level pinning due to AlInP surface states is highly relevant for device performance.[3] This holds also for the usage of AlInP as intermediate layer to form low-resistance ohmic contacts.[4] Previous work on III–V ternary alloys focuses primarily on the structural and electronic properties of the bulk, see, for example, other studies[5–8] and heterostructure interfaces.[9–12] There is lit- tle information available on the atomic structure and electronic properties of AlInP surfaces. It has been noted that different growth conditions lead to different degrees of CuPt ordering in the bulk material,[13,14] that is, alternating group III layers per- pendicular to the ½111� or ½111� directions. This is likely to be related to the formation of surface dimers, which induce strain in the material.[15,16] In case of GaInP, the CuPt-type ordering has been found to cause anisotropic effects in the electrical and optical properties.[17,18] Very recently, some models for clean AlInP(001) surfaces were established, which show that structures different from the ones known from binary III–V(001) surfaces may occur.[19] However, the calculations in the study by Ruiz Alvarado et al.[19] are restricted to clean surfaces. Often, AlInP is grown by metal– organic vapor-phase epitaxy (MOVPE) and chemical beam epi- taxy (CBE). Since hydrogen is present in MOVPE and CBE, it can be expected to be present at the AlInP surface as well.[20,21] Therefore, we here extend the previous study[19] to account for the possibility of surface-adsorbed hydrogen. A systematic search for stable Al0.5In0.5P(001) surface structures is performed, where the existence of hydrogen is L. J. Glahn, I. A. Ruiz Alvarado, S. Neufeld, W. G. Schmidt Lehrstuhl für Theoretische Materialphysik Universität Paderborn 33095 Paderborn, Germany E-mail: azahel@mail.upb.de M. A. Zare Pour, A. Paszuk, D. Ostheimer, S. Shekarabi, T. Hannappel Institut für Physik Technische Universität Ilmenau Gustav-Kirchhoff-Strase 5, 98693 Ilmenau, Germany O. Romanyuk Institute of Physics Academy of Sciences of the Czech Republic Cukrovarnicka 10, 16200 Prague, Czech Republic D. C. Moritz, J. P. Hofmann, W. Jaegermann Surface Science Laboratory Department of Materials and Earth Sciences Technische Universität Darmstadt Otto-Berndt-Strasse 3, 64287 Darmstadt, Germany The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/pssb.202200308. © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. DOI: 10.1002/pssb.202200308 Total energy and electronic structure calculations based on density functional theory are performed in order to determine the atomic structure and electronic properties of clean and hydrogen-adsorbed Al0.5In0.5P(001) surfaces. It is found that most of the stable surfaces obey the electron-counting rule and are char- acterized by surface atom dimerization. The dimer-related surface states are predicted to occur in the vicinity of the bulk band edges. For a very narrow range of preparation conditions, ab initio thermodynamics predicts metal atomic wires formed by surface cations. A surface covered with a monolayer of buckled phosphorus dimers, where half of the phosphorus atoms are hydrogen saturated, is found to be stable for metal–organic vapor-phase epitaxy growth conditions. The occurrence of this structure is confirmed by low-energy electron diffraction and X-ray photoelectron spectroscopy data measured on epitaxially grown Al0.52In0.48P(001) epilayers lattice matched to GaAs. RESEARCH ARTICLE www.pss-b.com Phys. Status Solidi B 2022, 259, 2200308 2200308 (1 of 6) © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH mailto:azahel@mail.upb.de https://doi.org/10.1002/pssb.202200308 http://creativecommons.org/licenses/by/4.0/ http://www.pss-b.com considered as an additional degree of freedom. The initial geom- etries for structure optimization are generated by systematically varying the surface stoichiometry of both CuPt–A and CuPt–B- type ordered Al0.5In0.5P crystals. The commonly accepted III–V(001) surface reconstructions[20–22] are included in the cal- culations, which probe computationally more than 80 surfaces. The computational predictions for typical MOVPE growth con- ditions are compared with low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS) data mea- sured on epitaxially grown Al0.52In0.48P(001) samples. 2. Computational Methodology In detail, density functional theory (DFT) calculations are per- formed using the Vienna ab initio simulation package (VASP).[23] The generalized gradient approximation (GGA) with the PBE functional[24] is used to model the electron exchange and correlation interaction. The electron–ion interaction is described by the projector-augmented wave (PAW) scheme.[25,26] The elec- tronic wave functions are expanded into plane waves up to a kinetic energy cutoff of 400 eV. The (001) surfaces are modeled by supercells containing 13 and 14 atomic layers for cation- and anion-terminated surfaces, respectively, and vacuum regions of �13.5 Å. 2� 2, 2� 4, and c-4� 4 translational symmetries are considered. The slab bottom dangling bonds are saturated with fractionally charged H atoms. The electric field resulting from the inequivalence of the two surfaces is taken into account by a dipole correction to the electrostatic potential. The atoms are structurally relaxed until they experience forces smaller than 0.02 eV Å�1. The calculations are performed at the equilibrium lattice parameter of Al0.5In0.5P calculated to be 5.751 Å. The Brillouin zone integration is performed using a k-point mesh corresponding to 64 sampling points in the primitive cell. In order to compare the various clean and hydrogen-covered surfaces energetically, the chemical potentials μAi of the respec- tive surface constituents need to be taken into account. The sur- face ground state is determined by the minimum of the thermodynamic potential Ω ¼ U � TS� X i μAi nAi (1) where U is the total energy of the system. In solids, the entropy term, TS, contributes very little to the difference inΩ under usual experimental conditions[27] and is neglected in the following. The chemical potentials μAi for Ai¼ In, Al, and P are restricted by their bulk values μAi ≤ μAi ;bulk (2) In addition, the stability of Al0.5In0.5P requires μAl þ μIn þ 2μP ¼ μAlInP2 ;bulk ¼ μAl;bulk þ μIn;bulk þ 2μP;bulk þ ΔHf ;AlInP2 (3) This allows for formulating the formation energy depending on ΔμIn and ΔμAl, that is, the variations of the In and Al chemical potentials with respect to their bulk values. For the heat of formationΔHf ;AlInP2 we calculate a value of�1.49 eV. The hydro- gen chemical potential, ΔμH, with respect to an isolated mole- cule, provides an additional and independent degree of freedom. In the approximation of a two-atomic ideal gas, it is written depending on partial pressure p and temperature T as ΔμHðp,TÞ ¼ kBT 2 ln pλ3 kBT � � � lnZrot � lnZvib � � (4) where kB is the Boltzmann constant, λ the de Broglie thermal wavelength of the H2 molecule, λ ¼ ffiffiffiffiffiffiffiffiffiffiffiffi 2πℏ2 mkBT s (5) and Zrot and Zvib are its rotational and vibrational partition func- tions, respectively. Zrot ¼ X∞ J¼0 ð2J þ 1Þ exp �JðJ þ 1Þℏ 2IkBT � � (6) Zvib ¼ ℏω 2 þ kBT ln 1� exp ℏω kBT � �� � (7) Here I is the moment of inertia and ω the fundamental mode of H2. By increasing the temperature, the hydrogen chemical potential is lowered, that is, less energy is gained by taking a H atom out of the reservoir and attaching it to the surface. A variation of the hydrogen chemical potential with respect to its molecular value at zero temperature of ΔμH¼�0.6 eV corre- sponds to the growth conditions in the experiment described below. 3. Results and Discussion 3.1. Surface Phase Diagram Figure 1 shows the calculated phase diagram of the Al0.5In0.5P(001) surface structures considered here. Only 10 out of the more than 80 candidate structures considered in our work turn out to be energetically relevant, that is, correspond to the surface ground state for specific preparation conditions. Schematic top views of these surfaces are compiled in Figure 2. The notation of structures, if not known taken from earlier studies, was chosen such as to indicate the translational symmetry, surface stoichiometry, and the presence of dimers (D) and mixed heterodimers (MD) of the respective surface. At hydrogen-deficient conditions (ΔμH¼�1 eV), P-dimer structures known from clean III–V(001) surfaces[22,28] dominate the phase diagram. This concerns the c-4� 4 structure for anion- rich surfaces and the β2-2� 4 surface for intermediate prepara- tion conditions. The occurrence of [110]-oriented P dimers in the P-rich c-4� 4 structure and of [110]-oriented dimers in 2� 4 sur- face reconstructions is in accordance with MOVPE-grown AlInP surfaces in N2 atmosphere.[13] Heterodimer structures featuring either In–P or Al–P dimers in the topmost layer occur for cation- rich preparation conditions. They differ from the mixed-dimer structure known from InP(001) by the staggered arrangement www.advancedsciencenews.com www.pss-b.com Phys. Status Solidi B 2022, 259, 2200308 2200308 (2 of 6) © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH http://www.advancedsciencenews.com http://www.pss-b.com of the second-layer cation dimers, due to the size mismatch between Al and In. For a broad range of intermediate values of the hydrogen chemical potential, ΔμH¼�0.2 ΔμH ¼ �0.2 · · · �0.8 eV, the 2D–2H surface is found to be stable; see Figure 1a. It corre- sponds to a 2� 2-reconstructed surface formed by P dimers; see Figure 2. Hydrogen is adsorbed in an alternating sequence on these buckled P dimers. Similar structures were observed for the (001) surface of InP, GaP, and InxGa1�xP prepared by gas- phase epitaxy.[20,21,29] The P dimers of the 2� 2-2D-2H surface break up at extremely H-rich conditions, ΔμH¼ 0 eV. In this case, the surface P atoms are alternatingly decorated by one and two hydrogens, forming the 2� 2-4P-6H structure. The hydrogen- Figure 1. a) Al0.5In0.5P(001) surface phase diagram calculated assuming P-rich surfaces and ΔμH¼�0.6 eV, that is, preparation conditions typical for vapor-phase epitaxy. Energies are given relative to the 2� 2-2D-2H surface. b) Dependence of the hydrogen chemical potential on temperature and partial pressure according to Equation (4). c) Complete surface phase diagram depending on the Al, In, and H chemical potentials. The thermodynamically allowed range of the chemical potentials according to Equation (2) and (3) is indicated by dashed lines. See Figure 2 for the notation of surface structures. Figure 2. Top and side views of stable relaxed clean as well as hydrogenated Al0.5In0.5P(001) surface structures identified in the present work. www.advancedsciencenews.com www.pss-b.com Phys. Status Solidi B 2022, 259, 2200308 2200308 (3 of 6) © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH http://www.advancedsciencenews.com http://www.pss-b.com covered surface P atoms are replaced by H-decorated In–P and Al–P heterodimers, if the surface is prepared in hydrogen and cation-rich conditions. Zunger et al.[30] suggested that the creation of subsurface selectivity for occupation by a small cation under the strained anion dimer rows and occupation by a large cation underneath the opening between dimer rows is the main thermodynamic driving force for CuPt ordering in GaInP alloys. The present calculations support this picture for AlInP. All stable P dimer structures identified here are characterized by P dimers that form above Al, while In occupies the corresponding subsurface positions between the P dimer rows; see Figure 2. No such correlation is found for the heterodimer structures. Mixed anion–cation dimers form on top of In, for example, in the 2� 2-2InMD-2H structure, as well as above Al, for example, in the 2� 1-AlMD-2H structure. This agrees with the observa- tion that the degree of atomic ordering of MOVPE-grown AlInP depends sensitively on the preparation conditions.[13] 3.2. Experiment In order to compare the theoretical calculations with the surface reconstruction of Al0.5In0.5P(001) obtained experimentally, thin Al0.52In0.48P(001) layers were prepared in a horizontal MOVPE reactor using H2 carrier gas at 100 mbar. The AlInP(001) epilayers were grown on GaInP(001) buffer layers on n-GaAs(001) substrate with 0.1° miscut toward the [111] direction. After deoxidation of GaAs(001) substrate under tertiarybutylarsine at 620 °C (surface temperature), 100 nm GaAs(001) and 100 nm GaInP(001) buffer layers were grown. Tertiarybutylphosphine (TBP), trimethylindium (TMIn), trime- thylgallium (TMGa), and trimethylaluminium (TMAl) were used as precursors. The epitaxially grown layers were doped n-type (�1� 1017 cm�3) using ditertiarybutyl silane (DTBSi). The Al0.52In0.48P(001) layer was grown at 100 mbar with a V/III ratio of 60 at 600 °C. To compensate the desorption of P from the AlInP(001) surface during cooling, the TBP precursor was kept open until reaching 300 °C. Subsequently, the TBP precursor was switched off and the sample was annealed for 10min at 310 °C to remove the excess of P and TBP precursor residuals from the surface. Lattice matching of the GaInP(100) and AlInP(001) layers to the substrate was confirmed ex situ by X-ray diffraction (XRD) in reference samples. To investigate the surface reconstruc- tion and chemical composition of the as-prepared AlInP(001) surfaces, selected samples were transferred from the MOVPE reactor in ultrahigh vacuum (UHV) via a dedicated UHV shuttle[31] for LEED (SPECS ErLEED 100-A) and XPS (SPECS Focus 500/Phoibos 150/1D-DLD-43-100, monochromated Al-Kα, 1486.74 eV). The preparation conditions (temperature and partial pressure) described above correspond to a H chemical potential of about �0.6 eV. For this chemical potential, the 2� 2-2D-2H surface is by far the most dominant structure in the phase diagram; see Figure 1. Figure 3 shows an XPS survey scan (top) as well as the Al 2p, In 3d5/2, and P 2p (bottom, from left to right) core-level photoemission lines of the 32 nm-thick AlInP(001) film. To increase the surface sensitivity of the measurement, the photoelectron take-off angle (with respect to the surface plane) was varied from 90° to 30° against normal emission (Figure 3, middle). The survey scan shows no oxygen or carbon on the sample. The fit of the XPS data shows that one component is sufficient to fit the Al 2p1/2, Al 2p3/2, and In 3d5/2 core-level peaks. The binding energy of metallic Al and In is at lower energy, at 72.75 and at 443.75 eV, respectively,[32] and not seen in the measured data. For the P 2p core level, the presence of an extra component is obvious. The data are fitted with two spin– orbit pairs, with the same FWHM and peak ratio of 2:1 for each pair. The second, lower-intensity component (red line) is shifted toward higher binding energy, and its binding energy can be cor- related with P dimers on the surface.[32] The intensity ratio of the peak related to the P dimers increased at the more surface- sensitive measurement (P 2p core level, middle), which confirms a P-rich surface. Thus, the XPS measurements exclude cation-rich models and suggest P dimer structures such as the 2� 2-2D-2H or the β2-2� 4 surface. To further investigate the surface structure, LEED was applied. Figure 4 shows the LEED diffraction patterns recorded at 52 eV (left hand side) and 64 eV (right hand side). The slightly diffuse LEED pattern and spots with blurred contrast indicate a reduced atomic order of the surface. This could be due to surface defects, lack of short-range order in the surface reconstruction, for exam- ple, due to missing hydrogen passivation, or due to traces of con- taminants such as oxygen. Aluminium containing surfaces are well known for their high affinity to oxygen incorporation.[19] Nevertheless, the LEED patterns clearly exhibit first- and half- 1400 1200 1000 800 600 400 200 0 76 75 74 73 446 444 132 130 128 In te ns ity ( a. u. ) data fit 30° 90° Al 2p 2p1/2 2p3/2 Binding Energy (eV) 30° 90° In 3d5/2 P-P P-III P-III P-P P 2p 30° 90° In Binding energy (eV) In te ns ity ( a. u. ) AlInP Survey scan mon. Al Ka, 2s 2p In 3d 2p Al P In 3p In MNN 4d 2s 90° In 3s In 3p Figure 3. XPS survey spectrum of a 32 nm-thick Al0.52In0.48P(001) layer (top) as well as the Al 2p, In 3d5/2, and P 2p core-level photoemission lines measured at 30° (middle) and 90° (bottom) take-off angle (with respect to surface plane). www.advancedsciencenews.com www.pss-b.com Phys. Status Solidi B 2022, 259, 2200308 2200308 (4 of 6) © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH http://www.advancedsciencenews.com http://www.pss-b.com order spots. In addition to the first-order spots, both diffraction patterns exhibit half-order spots indicating a 2� 1-like surface reconstruction (marked with white circles) and diffused streaks in �2 direction (indicated by white arrows). This LEED pattern is very similar to measurements on P-rich and partially hydrogen-covered InP(001) and GaP(001) surfaces: The adjacent rows of buckled P dimers stabilized by one hydrogen atom can be arranged in phase or out of phase.[20,33,34] The in-phase arrange- ment results in a p-2� 2 unit cell, while the out-of-phase arrange- ment corresponds to a c-4� 2 unit cell. Scanning tunneling microscopy (STM) scans of such P-rich InP(001) and GaP(001) surfaces show that those two domains are randomly distributed.[33,34] Their superposition leads to the 2� 1-like LEED pattern with characteristic streaks in the �2 half-order (see Figure 1 in the study by Kleinschmidt et al.[34]). This excludes the β2-2� 4 surfaces and is strong evidence that the surface prepared here corresponds to the 2� 2-2D-2H recon- struction predicted from ab initio thermodynamics. 3.3. Surface Electronic Properties Binary III–V surface reconstructions can be understood in terms of a simple electron counting model (ECM):[35] A surface struc- ture satisfies this model if all cation dangling bonds are empty and all anion dangling bonds are full, given the number of avail- able electrons. This model may be extended to hydrogen-covered surfaces[36] and is satisfied by the majority of the stable ternary surface structures identified here. In fact, the 2� 1-AlMD-2H structure is the only exception to the ECM. It is stable in a very narrow range of preparation conditions that are both cation and hydrogen rich. The 2� 1-AlMD-2H structure is not only the only stable struc- ture that does not comply with the ECM. It is also the only struc- ture that gives rise to a metallic band structure; see Figure 5. It features 1D Al–In atomic wires along the [110] direction, which are partially H decorated. The Al─In metal bonds result in a quasi-1 D electron band, which disperses along the atomic wire direction and pins the Fermi energy at midgap position. Similar electronic properties are calculated for the 2� 2-2InMD-2H structure. Here, an In–In atomic wire extends along the [110] direction and gives rise to two strongly dispersive electron bands. These two bands, one occupied and one empty, are separated by a small bandgap of about 0.2 eV and pin the Fermi energy at midgap position. However, these two structures are stable only in a very small window of preparation conditions, where the cation-rich surface is exposed to hydrogen. The β2-2� 4, the 2� 2-4P-6H, and, in particular the 2� 2-2D- 2H structures are far more prominent in the calculated surface phase diagram. They correspond to P-rich surfaces without hydrogen, in extremely hydrogen-rich, and at intermediate con- ditions, respectively. In case of the 2� 2-2D-2H structure, an occupied bound surface state is observed that extends slightly above the bulk valence band maximum (VBM), see Figure 5. This state is mainly related to the dangling bonds on the up atom of the phosphorus dimer. Exposing the P-rich AlInP(001) surface to very hydrogen-rich conditions leads to the 2� 2-4P-6H struc- ture and removes essentially all surface states from the band gap region. In fact, the only remaining surface state occurs at about 0.2 eV below the bulk VBM and corresponds to dangling bonds at under-coordinated surface P atoms. In case of the hydrogen-free β2-2� 4 surface, an occupied surface state is observed at about 64 eV [011] 52 eV Figure 4. LEED pattern of the Al0.52In0.48P(001) surface. See text. Figure 5. Band structures of the thermodynamically most relevant surface structures as well as of the 2� 1-AlMD-2H surface. Gray regions indicate the projected bulk band structure. ΓJ and ΓJ 0 are parallel to ½110� and ½110�, respectively. The orbital character of state (at the K point) is indicated for prominent surface states. See Figure 2 for notation of atoms. www.advancedsciencenews.com www.pss-b.com Phys. Status Solidi B 2022, 259, 2200308 2200308 (5 of 6) © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH http://www.advancedsciencenews.com http://www.pss-b.com 0.2 eV above the bulk VBM. This only weakly dispersive feature corresponds to an antibonding π* combination of pz orbitals local- ized at the third-layer P dimer. In addition, an empty surface state extends slightly into the region of the bulk bandgap. It is related to empty dangling bonds located at the threefold-coordinated sec- ond-layer cations. It is mainly In localized, but also has some Al contribution. Generally, with the exception of the 2� 1-AlMD-2H and 2� 2-2InMD-2H structures discussed above, it is found that all stable surfaces are characterized by occupied surface states close to the bulk VBM that are derived from surface anions or anion–cation bonds. The unoccupied surface states occur close to the bulk conduction band minimum and are cation related. 4. Conclusion In summary, it is shown that the AlInP(001) surface produced in the MOVPE environment is composed of a complete layer of phosphorus dimers. Half of the P dangling bonds on the dimers are hydrogen saturated, and the other half are filled with lone pairs of electrons. These lone pairs form a bound surface state slightly above the valence band maximum. DFT calculations sug- gest the existence of further structures, depending on the surface preparation conditions. P-rich surfaces are characterized by P dimers, while Al–P and In–P heterodimers form for more cation- rich surface preparation conditions. Most stable surface struc- tures obey the electron counting rule. Dimer-related surface states are found close to the bulk valence band maximum. Exposure of the surface to extreme hydrogen-rich conditions is predicted to quench the dimerization and remove all surface states from the region of the bulk bandgap. For cation- and hydrogen-rich preparation conditions, metal atomic wires may form on the surface. They give rise to quasi-1D surface bands that pin the Fermi energy in the midgap region. Acknowledgements Financial support by DFG (PAK981) is gratefully acknowledged. The authors thank the Paderborn Center for Parallel Computing (PC2) and the Höchstleistungs-Rechenzentrum Stuttgart (HLRS) for grants of high-performance computer time. Open Access funding enabled and organized by Projekt DEAL. Conflict of Interest The authors declare no conflict of interest. Data Availability Statement The data that support the findings of this study are available from the corresponding author upon reasonable request. Keywords AlInP, density functional theory, electronic properties, surface structures, X-ray photoelectron spectroscopy Received: July 11, 2022 Revised: July 29, 2022 Published online: August 19, 2022 [1] McEvoy’s Handbook of Photovoltaics: Fundamentals and Applications (Ed: S. A. Kalogirouo), Academic Press, Cambridge MA 2017. [2] C.-W. Kim, G.-Y. Park, J.-C. Shin, H.-J. Kim, Appl. Sci. 2022, 12, 601. [3] D. L. Lepkowski, T. Kasher, J. T. Boyer, D. J. Chmielewski, T. J. Grassman, S. A. Ringel, IEEE J. Photovoltaics 2020, 10, 758. [4] K. Iwata, H. Asahi, T. Ogura, J. Sumino, S. Gonda, A. Ohki, Y. Kawaguchi, T. Matsuoka, in Seventh Int. Conf. on Indium Phosphide and Related Materials, Sapporo, Japan 1995, pp. 183–186. [5] S. T. Murphy, A. Chroneos, C. Jiang, U. Schwingenschlögl, R. W. Grimes, Phys. Rev. B 2010, 82, 073201. [6] J. W. Nicklas, J. W. Wilkins, Appl. Phys. Lett. 2010, 97, 091902. [7] A. Abdollahi, M. M. Golzan, J. Mater. Sci. 2016, 51, 7343. [8] D. A. Beaton, T. Christian, K. Alberi, A. Mascarenhas, K. Mukherjee, E. A. Fitzgerald, J. Appl. Phys. 2013, 114, 203504. [9] S.-H. Wei, A. Zunger, Appl. Phys. Lett. 1998, 72, 2011. [10] Y.-H. Li, A. Walsh, S. Chen, W.-J. Yin, J.-H. Yang, J. Li, J. L. F. Da Silva, X. G. Gong, S.-H. Wei, Appl. Phys. Lett. 2009, 94, 212109. [11] L. Meier, C. Braun, T. Hannappel, W. G. Schmidt, Phys. Status Solidi B 2021, 258, 2000463. [12] L. Meier, W. G. Schmidt, Phys. Status Solidi B 2022, 259, 2100462. [13] Z. Jinghua, T. Xiaohong, T. Jinghua, CrystEngComm 2009, 11, 1068. [14] W. Yuan, D. C. Hall, J. Appl. Phys. 2013, 113, 103515. [15] S. B. Zhang, S. Froyen, A. Zunger, Appl. Phys. Lett. 1995, 67, 3141. [16] S. Froyen, A. Zunger, Phys. Rev. Lett. 1991, 66, 2132. [17] R. M. France, W. E. McMahon, J. Kang, M. A. Steiner, J. F. Geisz, J. Appl. Phys. 2014, 115, 053502. [18] G. Martín, C. Coll, L. López-Conesa, J. M. Rebled, E. Barrigón, I. García, I. Rey-Stolle, C. Algora, A. Cornet, S. Estradé, F. Peiró, ACS Appl. Electron. Mater. 2022, 4, 3478. [19] I. A. Ruiz Alvarado, M. Karmo, E. Runge, W. G. Schmidt, ACS Omega 2021, 6, 6297. [20] W. G. Schmidt, P. H. Hahn, F. Bechstedt, N. Esser, P. Vogt, A. Wange, W. Richter, Phys. Rev. Lett. 2003, 90, 126101. [21] P. H. Hahn, W. G. Schmidt, F. Bechstedt, O. Pulci, R. Del Sole, Phys. Rev. B 2003, 68, 033311. [22] W. G. Schmidt, Appl. Phys. A 2002, 75, 89. [23] G. Kresse, J. Furthmüller, Comput. Mater. Sci. 1996, 6, 15. [24] J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 1996, 77, 3865. [25] P. E. Blöchl, Phys. Rev. B 1994, 50, 17953. [26] G. Kresse, D. Joubert, Phys. Rev. B 1999, 59, 1758. [27] S. Wippermann, W. G. Schmidt, Phys. Rev. Lett. 2010, 105, 126102. [28] W. G. Schmidt, Appl. Phys. A 1997, 65, 581. [29] S. F. Cheng, Y. Sun, D. C. Law, S. B. Visbeck, R. F. Hicks, Surf. Sci. 2006, 600, 2924. [30] J. E. Bernard, S. Froyen, A. Zunger, Phys. Rev. B 1991, 44, 11178. [31] T. Hannappel, S. Visbeck, L. Töben, F. Willig, Rev. Sci. Instrum. 2004, 75, 1297. [32] J. Moulder, J. Chastain, Handbook of X-Ray Photoelectron Spectroscopy: A Reference Book of Standard Spectra For Identification and Interpretation of XPS Data, Physical Electronics Division, Perkin-Elmer Corporation, Eden Prairie, Minnesota 1992, ISBN 9780962702624. [33] L. Li, B.-K. Han, Q. Fu, R. F. Hicks, Phys. Rev. Lett. 1999, 82, 1879. [34] P. Kleinschmidt, H. Döscher, P. Vogt, T. Hannappel, Phys. Rev. B 2011, 83, 155316. [35] M. D. Pashley, Phys. Rev. B 1989, 40, 10481. [36] M. Karmo, I. A. Ruiz Alvarado, W. G. Schmidt, E. Runge, ACS Omega 2022, 7, 5064. www.advancedsciencenews.com www.pss-b.com Phys. Status Solidi B 2022, 259, 2200308 2200308 (6 of 6) © 2022 The Authors. physica status solidi (b) basic solid state physics published by Wiley-VCH GmbH http://www.advancedsciencenews.com http://www.pss-b.com Clean and Hydrogen-Adsorbed AlInP(001) Surfaces: Structures and Electronic Properties 1. Introduction 2. Computational Methodology 3. Results and Discussion 3.1. Surface Phase Diagram 3.2. Experiment 3.3. Surface Electronic Properties 4. Conclusion