Franz, M.; Das, A.; Chandola, S.; Kubicki, M.; Das, M.; Sette, A.; Corona, D.; Palummo, M.; Chiodo, L.; Schöder, R.; Chahar, P.; Fuhrmann, B.; Engelhardt, J.; Düren, O.; Rosenzweig, D.S.; Bakos, P.; Jakob, K.L.; Dähne, M.; Hogan, C.; Esser, N.; Glorius, F.: N-Heterocyclic Carbenes on a III-V Semiconductor: From Chain Formation to Ordered Monolayers. Angewandte Chemie - International Edition 64 (2025), p. e202511094/1-10
10.1002/anie.202511094
Open Accesn Version
Abstract:
N-Heterocyclic carbenes (NHCs) are established ligands for various surfaces, known for their strong binding, ability to form self-assembled monolayers, and modular structure. However, semiconductor surface modification with NHCs is still in its infancy despite its technological importance. Although previous studies focused on silicon, III-V compound semiconductors offer direct bandgaps and high electron mobilities, making them ideal for (opto-)electronics. This study examines the adsorption of different NHCs on GaAs, a prototypical III-V material, using scanning tunneling microscopy, density functional theory, X-ray photoelectron spectroscopy, low-energy electron diffraction, and reflectance anisotropy spectroscopy. Covalent binding to the surface and the formation of well-ordered NHC monolayers are observed, along with exceptionally large work function reductions. The unique structural features of NHCs enable precise control over film structure, ordering, and electronic properties.