Peer-Reviewed Journal Details Mandatory Fields Authors Tolloczko, Agata; Kopaczek, Jan; Szukiewicz, Rafal; Gocalinska, Agnieszka; Pelucchi, Emanuele; Hommel, Detlef; Kudrawiec, Robert Year 2018 Month Unknown Journal Journal of Physics D: Applied Physics Title Contactless electroreflectance study of the surface potential barrier in n-type and p-type InAlAs van Hoof structures lattice matched to InP Status In Press Times Cited WOS: 3 () Optional Fields Keywords Volume Issue Start Page End Page Abstract N-type and p-type In0.52Al0.48As van Hoof structures with various thicknesses of undoped In0.52Al0.48As layer (30, 60, 90, and 120 nm) were grown by metal-organic vapor phase epitaxy on InP substrates and studied by contactless electroreflectance (CER) at room temperature. The InAlAs bandgap related CER resonance followed by a strong Franz-Keldysh oscillation (FKO) of various periods was observed clearly for the two structures. This period was decreased with the decrease of thickness of undoped In0.52Al0.48As layer and was slightly narrower for p-type structures. The FKO period analysis indicates that the Fermi level is pinned 0.73¿0.02 eV below the conduction band at In0.52Al0.48As surface. This pinning was attributed to the surface reconstruction combined with the adsorption of oxygen and carbon atoms (consequence of air exposure) which were detected on the In0.52Al0.48As surface by X-ray photoelectron spectroscopy. Also, CER measurements repeated one year after the sample growth shows that the process of InAlAs oxidation in laboratory ambient is negligible and therefore this alloy can be used as a protective cap layer in InP-based heterostructures. Publisher Location ISBN / ISSN 1361-6463 Edition URL http://iopscience.iop.org/10.1088/1361-6463/aabf6b DOI Link 10.1088/1361-6463/aabf6b Grant Details Funding Body Science Foundation Ireland Grant Details SFI grants 12/RC/2276, 10/IN.1/I3000 and 15/IA/2864.