Studies of hydrogenated amorphous silicon

Technical Report · Sun Jul 01 00:00:00 EDT 1984

DOI:https://doi.org/10.2172/6781663· OSTI ID:6781663

Bishop, S G; Carlos, W E

This report discusses the results of probing the defect structure and bonding of hydrogenated amorphous silicon films using both nuclear magnetic resonance (NMR) and electron spin resonance (ESR). The doping efficiency of boron in a-Si:H was found to be less than 1%, with 90% of the boron in a threefold coordinated state. On the other hand, phosphorus NMR chemical shift measurements yielded a ration of threefold to fourfold P sites of roughly 4 to 1. Various resonance lines were observed in heavily boron- and phosphorus-doped films and a-SiC:H alloys. These lines were attributed to band tail states on twofold coordinated silicon. In a-SiC:H films, a strong resonance was attributed to dangling bonds on carbon atoms. ESR measurements on low-pressure chemical-vapor-deposited (LPCVD) a-Si:H were performed on samples. The defect density in the bulk of the films was 10/sup 17//cc with a factor of 3 increase at the surface of the sample. The ESR spectrum of LPCVD-prepared films was not affected by prolonged exposure to strong light. Microcrystalline silicon samples were also examined. The phosphorus-doped films showed a strong signal from the crystalline material and no resonance from the amorphous matrix. This shows that phosphorus is incorporated in the crystals and is active as a dopant. No signal was recorded from the boron-doped films.

• Research Organization: Naval Research Lab., Washington, DC (USA)
• DOE Contract Number: AC02-83CH10093
• OSTI ID: 6781663
• Report Number(s): SERI/STR-211-2393; ON: DE84013038
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360603 -- Materials-- Properties
AMORPHOUS STATE
BORON
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CRYSTAL DEFECTS
CRYSTAL DOPING
CRYSTAL STRUCTURE
DEPOSITION
ELECTRON SPIN RESONANCE
ELEMENTS
HYDROGEN ADDITIONS
MAGNETIC RESONANCE
NONMETALS
NUCLEAR MAGNETIC RESONANCE
PHOSPHORUS
PHOTOVOLTAIC
RESONANCE
SEMIMETALS
SILICON
SOLAR ENERGY
SURFACE COATING