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HL: Halbleiterphysik

HL 22: Grenz-/Oberfl
ächen

HL 22.5: Vortrag

Dienstag, 24. März 1998, 17:00–17:15, H17

Photoemission studies on Na/ZnSe(100) interfaces — •Zhonghui Chen¹, D. Eich¹, G. Reuscher², R. Fink¹, and E. Umbach¹ — ¹Experimentelle Physik II, und — ²Experimentelle Physik III, Universität Würzburg, Am Hubland, 97074 Würzburg

The metal-ZnSe(100) interface is an important aspect of ZnSe-based blue-green LEDs and lasers. Photoemission studies on metal-ZnSe interfaces provide microscopic insight into the chemical and electronic properties of the interface upon its formation. We report on a comprehensive study of the ZnSe(100)-c(2x2)-Na interface using X-ray (XPS) and UV (UPS) induced photoemission, and x-ray induced Auger spectrocopy (XAES). Spectra were taken after stepwise Na deposition onto a clean c(2x2) reconstructed ZnSe(100) surface up to a saturation coverage of approximately one monolayer Na. On the basis of the analysis of the Auger parameters of various Na, Zn and Se species, we propose an interface model for ZnSe(100)-(c2x2)-Na as follows: above a critical Na coverage (ca. 0.5 ML), a cation exchange reaction occurs between Na and Zn atoms; Zn atoms segregate on top of the Na overlayer forming metallic Zn. This interface model is further confirmed by both, sputtering-profiles and annealin! g experiments of ZnSe(100)-(c2x2)- Na(1 ML) interfaces.
(supported by DFG through SFB410, TP B3)