A (Gd 2 O 3 ) 1 - x (SiO 2 ) x (x = 0.5) gate dielectric film was deposited on an n-GaAs (001) substrate at various substrate temperatures. Bonding distribution of interfacial Ga and As was characterized by comparing the 3d and 3p photoelectron lines. Surface passivation using (NH 4 ) 2 S was employed to preserve a stable interface. Interfacial GaAs oxide was not formed after the deposition, since bonding transition from As-S to Ga-S bonds provides thermal stability and protective effect against oxidation. While, without the passivation, interfacial GaAs-oxides were continuously grown as the substrate temperature was increased. The energy band gap of (Gd 2 O 3 ) 0.5 (SiO 2 ) 0.5 was defined as 6.8eV using energy loss spectra of O 1s photoelectrons. The valence band maximum energy (E VBM ) of (Gd 2 O 3 ) 0.5 (SiO 2 ) 0.5 was determined to be 3.7eV. By arrangement of the measured energy bandgap and E VBM , the energy band structure of (Gd 2 O 3 ) 0.5 (SiO 2 ) 0.5 /GaAs system was demonstrated and an enhanced conduction band offset was observed.
Bibliographical noteFunding Information:
This work was supported by Korea Research Foundation Grant. (KRF-2003-041-000375).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films