TY - GEN A1 - Schmeißer, Dieter A1 - Irmscher, Klaus A1 - Wagner, Gerd T1 - Photoelectron spectra of Al dopants in 4H-SiC T2 - Materials Science & Engineering B N2 - Al-doped 4H-SiC epitaxial layers were grown in a hot-wall chemical vapor deposition (CVD) system on commercial 4H-SiC substrates (CREE). The incorporation of Aluminum has been studied in the concentration range from 2*1014cm-3 up to 3*1020cm-3. Epitaxial layers with doping concentration NA-ND> 1019cm-3 were studied by HV-TEM and synchrotron radiation investigations. In the concentration range from 1*1019cm-3 to 3*1020 cm-3, measured by SIMS and Hall investigations, no Aluminum precipitation were detected in the grown layers. For SiC samples with an Al concentration of 1020cm-3 we have been able to detect the Al2p photoemission signal. The Al2p signal is recorded through the oxide layer (thickness of about 0.4nm), it has a main contribution at a binding energy of 73eV which corresponds to the energy typical for elemental Al0. In spectra excited with higher photon energies the sampled photoelectrons originate from deeper layers. In these data we notice an additional shoulder in the Al2p signal at around 71eV. The evidence of two contributions is attributed to the fact that Al is incorporated at different lattice sites. As the latter data represent more bulk like properties we argue that Al in the bulk SiC occupies both, substitutional lattice sites and interstitial sites while in the surface near regions Al is found only at substitutional lattice sites. KW - Photoelectron KW - Spectra KW - 4H-SiC Y1 - 2003 SN - 0921-5107 SN - 1873-4944 VL - 102 IS - 1-3 SP - 284 EP - 288 ER - TY - GEN A1 - Janowitz, Christoph A1 - Scherer, Valentina A1 - Mohamed, Mansour A1 - Krapf, Alica A1 - Dwelk, Helmut A1 - Manzke, Recardo A1 - Galazka, Zbigniew A1 - Uecker, Reinhard A1 - Irmscher, Klaus A1 - Fornari, Robert A1 - Michling, Marcel A1 - Schmeißer, Dieter T1 - Experimental electronic structure of In2O3 and Ga2O3 T2 - New Journal of Physics Y1 - 2011 SN - 1367-2630 VL - 13 IS - 8 SP - 085014 ER -