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O: Oberflächenphysik

O 31: Halbleiteroberfl
ächen (II)

O 31.6: Vortrag

Donnerstag, 14. März 2002, 12:30–12:45, H45

Band Alignment at Crystalline Pr₂O₃/Si(001) Heterojunctions — •Hans-Joachim Müssig, Jing Ping Liu, and Hans-Jörg Osten — IHP, Im Technologiepark 25, D-15236 Frankfurt (Oder), Germany

We report the experimental results on the band alignment of Pr₂O₃ films on Si(001) as prepared by molecular beam epitaxy. Using X-ray photoelectron spectroscopy, we obtain a valence band offset at the Pr₂O₃/Si(001) interface of (1.1 ± 0.2) eV. High field tunneling was used to extract the conduction band offset of (0.5 - 1.5) eV. Thus, the Pr₂O₃/Si(001) interface band alignment is symmetric, desired for applying such materials in both n- and p-type devices. The bandgap of bulk Pr₂O₃ should be between 2.5 and 3.9 eV. Using scanning tunneling spectroscopy, we find a surface-state bandgap of about 3.2 eV for monolayer coverage. In agreement with recent pseudopotential calculations, the electron masses in the oxide appear to be very large. This effect, together with the suitable band offsets lead to the unusually low leakage currents measured recently.