Potential variations around grain boundaries in impurity-doped BaSi₂ epitaxial films evaluated by Kelvin probe force microscopy
- Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)
- Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)
- Institute for Photovoltaics, University of Stuttgart, Stuttgart 70569 (Germany)
Potential variations around the grain boundaries (GBs) in antimony (Sb)-doped n-type and boron (B)-doped p-type BaSi₂ epitaxial films on Si(111) were evaluated by Kelvin probe force microscopy. Sb-doped n-BaSi₂ films exhibited positively charged GBs with a downward band bending at the GBs. The average barrier height for holes was approximately 10 meV for an electron concentration n ≈ 10¹⁷ cm⁻³. This downward band bending changed to upward band bending when n was increased to n = 1.8 × 10¹⁸cm⁻³. In the B-doped p-BaSi₂ films, the upward band bending was observed for a hole concentration p ≈ 10¹⁸cm⁻³. The average barrier height for electrons decreased from approximately 25 to 15 meV when p was increased from p = 2.7 × 10¹⁸ to p = 4.0 × 10¹⁸ cm⁻³. These results are explained under the assumption that the position of the Fermi level E{sub f} at GBs depends on the degree of occupancy of defect states at the GBs, while E{sub f} approached the bottom of the conduction band or the top of the valence band in the BaSi₂ grain interiors with increasing impurity concentrations. In both cases, such small barrier heights may not deteriorate the carrier transport properties. The electronic structures of impurity-doped BaSi₂ are also discussed using first-principles pseudopotential method to discuss the insertion sites of impurity atoms and clarify the reason for the observed n-type conduction in the Sb-doped BaSi₂ and p-type conduction in the B-doped BaSi₂.
- OSTI ID:
- 22305707
- Journal Information:
- Journal of Applied Physics, Vol. 116, Issue 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Chemical vapor deposition of thin-film polycrystalline Si for low-cost solar cells. Third quarterly technical progress report, February 2, 1980-May 2, 1980
Structural, microstructural, and electrical properties of gold films and Schottky contacts on remote plasma-cleaned, n-type ZnO{l_brace}0001{r_brace} surfaces
Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIMONY ADDITIONS
APPROXIMATIONS
ATOMS
BARIUM SILICATES
BORON ADDITIONS
CARRIERS
CONCENTRATION RATIO
CRYSTAL DEFECTS
DOPED MATERIALS
ELECTRIC POTENTIAL
ELECTRONIC STRUCTURE
ELECTRONS
EPITAXY
FERMI LEVEL
FILMS
GRAIN BOUNDARIES
HOLES
IMPURITIES
SILICON