Dresden 2003 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 24: Poster

DS 24.12: Poster

Dienstag, 25. März 2003, 14:30–17:00, P2a

Photoemission Investigations of Nitrided III-V Semiconductor Surfaces - Resonant Photoemission and Time-Dependent Effects — •J.-D. Hecht¹, L. Zhang², F. Frost¹, and T. Chassé^1,2 — ¹Institut f"ur Oberfl"achenmodifizierung, Permoserstrasse 15, 04318 Leipzig — ²Wilhelm-Ostwald-Institut f"ur Physikalische und Theoretische Chemie, Universit"at 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 processinherent implantation of interstitial molecular nitrogen. The spectral features corresponding to N₂ 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.