Photoemission spectroscopy of heterojunctions of hydrogenated amorphous silicon with silicon oxide and nitride
The growth and electronic structure of a-Si:H/a-SiN/sub x/:H and a-Si:H/a-SiO/sub x/:H heterojunctions have been studied by photoemission spectroscopy. Si 2p core-level photoemission was used to profile the chemical composition microscopically across the interfaces. With the exception of the SiO/sub x/-on-Si interface, which due to initial plasma oxidation is graded over approx.3 A, the interfaces are atomically abrupt. The offset energies between the a-Si:H valence-band edge and that of a-SiN/sub x/:H and a-SiO/sub x/:H, determined by valence-band photoemission, are 1.2 and 4.0 eV, respectively. Based on the fact that the offset energy is independent of a-Si:H layer thickness down to monolayer dimensions, we concluded that hole wave functions in a-Si:H are extremely localized. From the variation of the intensity of the Si-H bonding peak, located at approx.7 eV below the Fermi level, as a function of a-Si:H overlayer thickness, we determined that there are approx.2 x 10/sup 15/ cm/sup -2/ extra H atoms incorporated at the interface region to compensate for the large lattice mismatch at the interface. The invariance of the Si L/sub 2,3/ absorption edge with a-Si:H overlayer thickness indicates that the range of the core-hole exciton is less than 6 A.
- Research Organization:
- Exxon Research and Engineering Company, Clinton Township, Route 22 East, Annandale, New Jersey 08801
- OSTI ID:
- 6439521
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 39:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HETEROJUNCTIONS
ELECTRONIC STRUCTURE
GROWTH
PHOTOELECTRON SPECTROSCOPY
SILANES
SILICON NITRIDES
SILICON OXIDES
AMORPHOUS STATE
CHEMICAL VAPOR DEPOSITION
EXCITONS
HOLES
SYNCHROTRON RADIATION
ULTRAHIGH VACUUM
WAVE FUNCTIONS
BREMSSTRAHLUNG
CHALCOGENIDES
CHEMICAL COATING
DEPOSITION
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
FUNCTIONS
HYDRIDES
HYDROGEN COMPOUNDS
JUNCTIONS
NITRIDES
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
QUASI PARTICLES
RADIATIONS
SEMICONDUCTOR JUNCTIONS
SILICON COMPOUNDS
SPECTROSCOPY
SURFACE COATING
360603* - Materials- Properties