Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 50: Nitrides: Preparation and Characterization

HL 50.3: Vortrag

Mittwoch, 22. März 2017, 10:15–10:30, POT 251

Hydrogen-induced modifications of N-polar InN surface properties — •Anja Himmerlich, Stefan Krischok, and Marcel Himmerlich — Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, Germany

Indium nitride (InN) is a III-V semiconductor with controversially discussed surface electronic properties. Especially the normally observed high surface electron concentration is under debate. In contrast to In-polar InN, as-grown N-polar InN shows a reduced surface electron accumulation, that however significantly changes during storage in ambient conditions [1]. Here we present investigations on the interaction of atomic hydrogen, a dissociation product of different ambient molecules, with as-grown N-polar InN using in situ photoelectron spectroscopy. Within this study changes in the surface electronic properties, including band alignment and work function, as well as chemical bonding states of the substrate and adsorbates are characterized. We demonstrate that hydrogen preferentially bonds to the surface nitrogen atoms, resulting in the disappearance of nitrogen dangling-bond-related occupied surface state close to the valence band edge and the formation of new occupied electron states at the conduction band edge. The decrease in work function during adsorption and the increase in surface downward band bending confirm that hydrogen is acting as electron donor at N-polar InN surfaces and therefore has to be considered as one main reason for the increased electron accumulation observed for samples exposed to ambient conditions [2]. [1] Appl. Phys. Lett. 102, 231602 (2013); [2] Phys. Rev. B 91, 245305 (2015).