Regensburg 2002 – wissenschaftliches Programm

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O: Oberflächenphysik

O 13: Postersitzung (Adsorption an Oberfl
ächen, Elektronische Struktur, Magnetismus in reduzierten Dimensionen, Epitaxie und Wachstum, Halbleiteroberfl
ächen und -grenzfl
ächen, Organische Dünnschichten)

O 13.58: Poster

Montag, 11. März 2002, 18:00–21:00, Bereich C

Photoemission Investigations of Nitrided III-V Semiconductor Surfaces - Resonant Photoemission and Time-Dependent Effects — •J.-D. Hecht¹, F. Frost¹, L. Zhang², and T. Chassé¹ — ¹Institut für Oberflächenmodifizierung, Permoserstraße 15, 04318 Leipzig — ²Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, 04103 Leipzig

The subject of this work is the investigation of surface nitridation using in situ core and valence level photoemission measurements. GaAs, InAs, InP, and InSb(100) samples were nitrided using low-energy N₂⁺ bombardment at different ion beam parameters and substrate temperatures. A detailed analysis of the sustrate core levels and the N 1s peaks reveals the presence of nitrides and interstitial nitrogen. We further focussed on the observation of resonant photoemission for the investigation of surface nitridation. N 1s and valence band spectra were recorded at different excitation energies and in particular near the 1s-π* absorption energy of molecular nitrogen. Valence band spectra taken at resonance conditions reveal a strong enhancement of a feature that may be attributed to an occupied MO of N₂, and therefore provide new evidence for a process-inherent implantation of interstitial molecular nitrogen (N_i). The spectral features corresponding to N_i are subject of a strong time-dependent effect, which may be due to radiation induced diffusion caused by the intense photon flux at the U49/2 undulator beamline at BESSY II.